diff --git a/R/helpers.R b/R/helpers.R
index e66b93e..3a2596c 100644
--- a/R/helpers.R
+++ b/R/helpers.R
@@ -37,7 +37,12 @@
 
   for(i in seq_along(idVars)){
     # set the desired type
-    class(input[[which(names(idVars)[i] == names(input))]]) <- idVars[[i]]$datype
+
+    if(idVars[[i]]$datype == "Date"){
+      input[[which(names(idVars)[i] == names(input))]] <- as.Date(input[[which(names(idVars)[i] == names(input))]], tryFormats = c("%Y-%m-%d"), optional = TRUE)
+    } else {
+      class(input[[which(names(idVars)[i] == names(input))]]) <- idVars[[i]]$datype
+    }
 
   }
 
diff --git a/R/setIDVar.R b/R/setIDVar.R
index 860c501..f610e93 100644
--- a/R/setIDVar.R
+++ b/R/setIDVar.R
@@ -9,7 +9,9 @@
 #' @param name [\code{character(1)}]\cr Name of the new identifying variable.
 #' @param type [\code{character(1)}]\cr data type of the new identifying
 #'   variable. Possible values are \code{"c/character"}, \code{"i/integer"},
-#'   \code{"n/numeric"}, \code{"l/logical"}, \code{"D/date"} or \code{"_/skip"}.
+#'   \code{"n/numeric"}, \code{"l/logical"}, \code{"D/Date"} or \code{"_/skip"}.
+#'   For \code{"D/Date"}, the value has to follow the form \code{YYYY-MM-DD},
+#'   where dates that don't match that are replaced by NA.
 #' @param value [\code{character(1)}]\cr In case the variable is an implicit
 #'   variable (i.e., which is not in the origin table), specify it here.
 #' @param columns [\code{integerish(.)}]\cr The column(s) in which the
diff --git a/man/setIDVar.Rd b/man/setIDVar.Rd
index ea43d7b..5ea79fd 100644
--- a/man/setIDVar.Rd
+++ b/man/setIDVar.Rd
@@ -25,7 +25,9 @@ information).}
 
 \item{type}{[\code{character(1)}]\cr data type of the new identifying
 variable. Possible values are \code{"c/character"}, \code{"i/integer"},
-\code{"n/numeric"}, \code{"l/logical"}, \code{"D/date"} or \code{"_/skip"}.}
+\code{"n/numeric"}, \code{"l/logical"}, \code{"D/Date"} or \code{"_/skip"}.
+For \code{"D/Date"}, the value has to follow the form \code{YYYY-MM-DD},
+where dates that don't match that are replaced by NA.}
 
 \item{value}{[\code{character(1)}]\cr In case the variable is an implicit
 variable (i.e., which is not in the origin table), specify it here.}