diff --git a/bin/pycbc_convertinjfiletohdf b/bin/pycbc_convertinjfiletohdf
index f0557fa03b2..c871d9a4189 100755
--- a/bin/pycbc_convertinjfiletohdf
+++ b/bin/pycbc_convertinjfiletohdf
@@ -151,7 +151,11 @@ class LVKNewStyleInjectionSet(object):
             elif lvk_name == 't_co_gps_add':
                 continue
             else:
-                data[pycbc_name] = self.inj_file[f'{self.subdir}/{lvk_name}'][:]
+                lvk_file_dset = self.inj_file[f'{self.subdir}/{lvk_name}']
+                if lvk_file_dset.dtype.char in ['U', 'O']:
+                    data[pycbc_name] = lvk_file_dset[:].astype('S')
+                else:
+                    data[pycbc_name] = lvk_file_dset[:]
         return data
 
 
@@ -187,4 +191,4 @@ if injclass is not None:
     CBCHDFInjectionSet.write(args.output_file, samples)
 else:
     # Assume the injection is a HDF file (PyCBC format), only make a copy
-    shutil.copy(args.injection_file, args.output_file)
\ No newline at end of file
+    shutil.copy(args.injection_file, args.output_file)