diff --git a/libmariadb/mariadb_lib.c b/libmariadb/mariadb_lib.c
index f063a932..54ee2068 100644
--- a/libmariadb/mariadb_lib.c
+++ b/libmariadb/mariadb_lib.c
@@ -698,6 +698,11 @@ my_bool _mariadb_set_conf_option(MYSQL *mysql, const char *config_option, const
   if (config_option)
   {
     int i;
+    char *c;
+    
+    /* CONC-395: replace underscore "_" by dash "-" */
+    while ((c= strchr(config_option, '_')))
+      *c= '-';
 
     for (i=0; mariadb_defaults[i].conf_key; i++)
     {
diff --git a/unittest/libmariadb/misc.c b/unittest/libmariadb/misc.c
index f2b7a9fc..babcb1dc 100644
--- a/unittest/libmariadb/misc.c
+++ b/unittest/libmariadb/misc.c
@@ -1345,10 +1345,51 @@ static int test_conc384(MYSQL *my __attribute__((unused)))
   return OK;
 }
 
+#ifndef _WIN32
+static int test_conc395(MYSQL *unused __attribute__((unused)))
+{
+  MYSQL *mysql;
+  FILE *fp= NULL;
+  const char *env= getenv("MYSQL_TMP_DIR");
+  char cnf_file1[FN_REFLEN + 1];
+
+  if (travis_test)
+    return SKIP;
+
+  if (!env)
+    env= "/tmp";
+
+  setenv("HOME", env, 1);
+
+  snprintf(cnf_file1, FN_REFLEN, "%s%c.my.cnf", env, FN_LIBCHAR);
+
+  FAIL_IF(!access(cnf_file1, R_OK), "access");
+
+  mysql= mysql_init(NULL);
+  fp= fopen(cnf_file1, "w");
+  FAIL_IF(!fp, "fopen");
+
+  /* Mix dash and underscore */
+  fprintf(fp, "[client]\ndefault_character-set=latin2\n");
+  fclose(fp);
+
+  mysql_options(mysql, MYSQL_READ_DEFAULT_GROUP, "");
+  my_test_connect(mysql, hostname, username, password,
+                  schema, 0, socketname, 0);
+
+  remove(cnf_file1);
+
+  FAIL_IF(strcmp(mysql_character_set_name(mysql), "latin2"), "expected charset latin2");
+  mysql_close(mysql);
+  return OK;
+}
+#endif
+
 struct my_tests_st my_tests[] = {
   {"test_conc384", test_conc384, TEST_CONNECTION_NONE, 0, NULL, NULL},
 #ifndef _WIN32
   {"test_mdev12965", test_mdev12965, TEST_CONNECTION_DEFAULT, 0, NULL, NULL},
+  {"test_conc395", test_conc395, TEST_CONNECTION_DEFAULT, 0, NULL, NULL},
 #endif
   {"test_wl6797", test_wl6797, TEST_CONNECTION_DEFAULT, 0, NULL, NULL},
   {"test_server_status", test_server_status, TEST_CONNECTION_DEFAULT, 0, NULL, NULL},