diff --git a/omas/omas_ascii.py b/omas/omas_ascii.py
index 596bbae0..77b79d3f 100644
--- a/omas/omas_ascii.py
+++ b/omas/omas_ascii.py
@@ -8,7 +8,7 @@
 
 
 def identify_imas_type(value):
-    if isinstance(value, (str, numpy.bytes_, numpy.unicode_, numpy.str_)):
+    if isinstance(value, (str, numpy.bytes_, numpy.str_)):
         dtype = dict(type='50 (CHAR_DATA)', dim=1, size=(len(value),))
     elif isinstance(value, (float, numpy.floating)):
         dtype = dict(type='52 (DOUBLE_DATA)', dim=0)
diff --git a/omas/omas_core.py b/omas/omas_core.py
index 203121b7..5841e8ca 100644
--- a/omas/omas_core.py
+++ b/omas/omas_core.py
@@ -57,7 +57,7 @@ def force_imas_type(value):
             value = value.values
     if isinstance(value, numpy.ndarray) and not len(value.shape):
         value = value.item()
-    if isinstance(value, (numpy.bytes_, numpy.unicode_, numpy.str_)):
+    if isinstance(value, (numpy.bytes_, numpy.str_)):
         value = value.item()
     elif isinstance(value, (float, numpy.floating)):
         value = float(value)