diff --git a/src/jogasaki/serializer/value_output.cpp b/src/jogasaki/serializer/value_output.cpp
index 8b36602c..d27c4b1c 100644
--- a/src/jogasaki/serializer/value_output.cpp
+++ b/src/jogasaki/serializer/value_output.cpp
@@ -519,4 +519,36 @@ bool write_row_begin(
     return true;
 }
 
+bool write_blob(
+        std::uint64_t provider,
+        std::uint64_t object_id,
+        buffer_view::iterator& position,
+        buffer_view::const_iterator end) {
+    if (buffer_remaining(position, end) < 1
+            + sizeof(std::uint64_t)
+            + sizeof(std::uint64_t)) {
+        return false;
+    }
+    write_fixed8(header_blob, position, end);
+    write_fixed(provider, position, end);
+    write_fixed(object_id, position, end);
+    return true;
+}
+
+bool write_clob(
+        std::uint64_t provider,
+        std::uint64_t object_id,
+        buffer_view::iterator& position,
+        buffer_view::const_iterator end) {
+    if (buffer_remaining(position, end) < 1
+            + sizeof(std::uint64_t)
+            + sizeof(std::uint64_t)) {
+        return false;
+    }
+    write_fixed8(header_clob, position, end);
+    write_fixed(provider, position, end);
+    write_fixed(object_id, position, end);
+    return true;
+}
+
 } // namespace jogasaki::serializer
diff --git a/src/jogasaki/serializer/value_output.h b/src/jogasaki/serializer/value_output.h
index dbca2662..c53a864e 100644
--- a/src/jogasaki/serializer/value_output.h
+++ b/src/jogasaki/serializer/value_output.h
@@ -50,7 +50,6 @@ bool write_null(
  * @param value the value to write
  * @param position the buffer content iterator
  * @param end the buffer ending position
- * @return the retrieved value
  * @return true the operation successfully completed
  * @return false the remaining buffer is too short to write contents
  */
@@ -65,7 +64,6 @@ bool write_int(
  * @param value the value to write
  * @param position the buffer content iterator
  * @param end the buffer ending position
- * @return the retrieved value
  * @return true the operation successfully completed
  * @return false the remaining buffer is too short to write contents
  */
@@ -80,7 +78,6 @@ bool write_float4(
  * @param value the value to write
  * @param position the buffer content iterator
  * @param end the buffer ending position
- * @return the retrieved value
  * @return true the operation successfully completed
  * @return false the remaining buffer is too short to write contents
  */
@@ -96,7 +93,6 @@ bool write_float8(
  * @param value the value to write
  * @param position the buffer content iterator
  * @param end the buffer ending position
- * @return the retrieved value
  * @return true the operation successfully completed
  * @return false the remaining buffer is too short to write contents
  */
@@ -113,7 +109,6 @@ bool write_decimal(
  * @param value the value to write
  * @param position the buffer content iterator
  * @param end the buffer ending position
- * @return the retrieved value
  * @return true the operation successfully completed
  * @return false the remaining buffer is too short to write contents
  */
@@ -130,7 +125,6 @@ bool write_character(
  * @param value the value to write
  * @param position the buffer content iterator
  * @param end the buffer ending position
- * @return the retrieved value
  * @return true the operation successfully completed
  * @return false the remaining buffer is too short to write contents
  */
@@ -147,7 +141,6 @@ bool write_octet(
  * @param value the value to write
  * @param position the buffer content iterator
  * @param end the buffer ending position
- * @return the retrieved value
  * @return true the operation successfully completed
  * @return false the remaining buffer is too short to write contents
  */
@@ -165,7 +158,6 @@ bool write_bit(
  * @param number_of_bits the number of bits to write
  * @param position the buffer content iterator
  * @param end the buffer ending position
- * @return the retrieved value
  * @return true the operation successfully completed
  * @return false the remaining buffer is too short to write contents
  * @throws std::out_of_range if `number_of_bits` is too large for `blocks`
@@ -182,7 +174,6 @@ bool write_bit(
  * @param value the value to write
  * @param position the buffer content iterator
  * @param end the buffer ending position
- * @return the retrieved value
  * @return true the operation successfully completed
  * @return false the remaining buffer is too short to write contents
  */
@@ -197,7 +188,6 @@ bool write_date(
  * @param value the value to write
  * @param position the buffer content iterator
  * @param end the buffer ending position
- * @return the retrieved value
  * @return true the operation successfully completed
  * @return false the remaining buffer is too short to write contents
  */
@@ -213,7 +203,6 @@ bool write_time_of_day(
  * @param timezone_offset the timezone offset (in minute) to write
  * @param position the buffer content iterator
  * @param end the buffer ending position
- * @return the retrieved value
  * @return true the operation successfully completed
  * @return false the remaining buffer is too short to write contents
  */
@@ -229,7 +218,6 @@ bool write_time_of_day_with_offset(
  * @param value the value to write
  * @param position the buffer content iterator
  * @param end the buffer ending position
- * @return the retrieved value
  * @return true the operation successfully completed
  * @return false the remaining buffer is too short to write contents
  */
@@ -245,7 +233,6 @@ bool write_time_point(
  * @param timezone_offset the timezone offset (in minute) to write
  * @param position the buffer content iterator
  * @param end the buffer ending position
- * @return the retrieved value
  * @return true the operation successfully completed
  * @return false the remaining buffer is too short to write contents
  */
@@ -261,7 +248,6 @@ bool write_time_point_with_offset(
  * @param value the value to write
  * @param position the buffer content iterator
  * @param end the buffer ending position
- * @return the retrieved value
  * @return true the operation successfully completed
  * @return false the remaining buffer is too short to write contents
  */
@@ -278,7 +264,6 @@ bool write_datetime_interval(
  * @param size the number of elements in the array, must be less than `2^31` for interoperability
  * @param position the buffer content iterator
  * @param end the buffer ending position
- * @return the consequent number of elements in the array
  * @return true the operation successfully completed
  * @return false the remaining buffer is too short to write contents
  * @throws std::out_of_range if size is out of range
@@ -296,7 +281,6 @@ bool write_array_begin(
  * @param size the number of elements in the row, must be less than `2^31` for interoperability
  * @param position the buffer content iterator
  * @param end the buffer ending position
- * @return the consequent number of elements in the row
  * @return true the operation successfully completed
  * @return false the remaining buffer is too short to write contents
  * @throws std::out_of_range if size is out of range
@@ -306,6 +290,36 @@ bool write_row_begin(
         buffer_view::iterator& position,
         buffer_view::const_iterator end);
 
-// FIXME: impl blob, clob
+/**
+ * @brief puts `blob` entry onto the current position.
+ * @details This operation will advance the buffer iterator to the next entry, only if it is successfully completed.
+ * @param provider the provider of the blob, see jogasaki::proto::sql::common::LargeObjectProvider
+ * @param object_id the id of the blob object
+ * @param position the buffer content iterator
+ * @param end the buffer ending position
+ * @return true the operation successfully completed
+ * @return false the remaining buffer is too short to write contents
+ */
+bool write_blob(
+        std::uint64_t provider,
+        std::uint64_t object_id,
+        buffer_view::iterator& position,
+        buffer_view::const_iterator end);
+
+/**
+ * @brief puts `clob` entry onto the current position.
+ * @details This operation will advance the buffer iterator to the next entry, only if it is successfully completed.
+ * @param provider the provider of the clob, see jogasaki::proto::sql::common::LargeObjectProvider
+ * @param object_id the id of the clob object
+ * @param position the buffer content iterator
+ * @param end the buffer ending position
+ * @return true the operation successfully completed
+ * @return false the remaining buffer is too short to write contents
+ */
+bool write_clob(
+        std::uint64_t provider,
+        std::uint64_t object_id,
+        buffer_view::iterator& position,
+        buffer_view::const_iterator end);
 
 } // namespace jogasaki::serializer
diff --git a/src/jogasaki/serializer/value_writer.h b/src/jogasaki/serializer/value_writer.h
index 0eaa77c0..44b3d12f 100644
--- a/src/jogasaki/serializer/value_writer.h
+++ b/src/jogasaki/serializer/value_writer.h
@@ -307,7 +307,37 @@ class value_writer {
         return writer_->write(buf.data(), write_size);
     }
 
-    // FIXME: impl blob, clob
+    /**
+     * @brief puts `blob` entry onto the current position.
+     * @param provider the provider of the blob, see jogasaki::proto::sql::common::LargeObjectProvider
+     * @param object_id the id of the blob object
+     */
+    result_type write_blob(std::uint64_t provider, std::uint64_t object_id) {
+        auto buf = buffer();
+        auto *iter = buf.begin();
+        auto ret = ::jogasaki::serializer::write_blob(provider, object_id, iter, buf.end());
+        BOOST_ASSERT(ret); // NOLINT
+        (void) ret;
+
+        auto write_size = static_cast<size_type>(std::distance(buf.begin(), iter));
+        return writer_->write(buf.data(), write_size);
+    }
+
+    /**
+     * @brief puts `clob` entry onto the current position.
+     * @param provider the provider of the clob, see jogasaki::proto::sql::common::LargeObjectProvider
+     * @param object_id the id of the clob object
+     */
+    result_type write_clob(std::uint64_t provider, std::uint64_t object_id) {
+        auto buf = buffer();
+        auto *iter = buf.begin();
+        auto ret = ::jogasaki::serializer::write_clob(provider, object_id, iter, buf.end());
+        BOOST_ASSERT(ret); // NOLINT
+        (void) ret;
+
+        auto write_size = static_cast<size_type>(std::distance(buf.begin(), iter));
+        return writer_->write(buf.data(), write_size);
+    }
 
 private:
     std::vector<buffer_view::value_type> buffer_;