diff --git a/machine_learning_hep/mlperformance.py b/machine_learning_hep/mlperformance.py
index 5ab2595162..60c35dd798 100644
--- a/machine_learning_hep/mlperformance.py
+++ b/machine_learning_hep/mlperformance.py
@@ -197,8 +197,8 @@ def plot_roc_ovo(names_, classifiers_, suffix_, x_train, y_train,
                          linewidth=5.0)
         global_roc_auc = roc_auc_score(y_train, y_score, average="macro", multi_class='ovo')
         plt.plot([], [], ' ', label=f'Unweighted average OvO ROC AUC: {global_roc_auc:.2f}')
-        ax.set_xlabel("First class efficiency", fontsize=20)
-        ax.set_ylabel("Second class efficiency", fontsize=20)
+        ax.set_xlabel("First class efficiency", fontsize=30)
+        ax.set_ylabel("Second class efficiency", fontsize=30)
         ax.set_title(f"ROC one vs. one {name}", fontsize=30)
         ax.legend(loc="lower right", frameon=False, fontsize=25)
         ax.set_xlim([-0.05, 1.05])