diff --git a/CHANGES.txt b/CHANGES.txt
index 7b8fde184b..36a980c339 100644
--- a/CHANGES.txt
+++ b/CHANGES.txt
@@ -1,6 +1,7 @@
 3.11.17
  * Fix NPE when using udfContext in UDF after a restart of a node (CASSANDRA-18739)
 Merged from 3.0:
+ * Make alternation of a user type validate the same way as creation of a user type does (CASSANDRA-18585)
  * Backport of CASSANDRA-16905 Further restrict schema column drop/recreate conversions (CASSANDRA-18760)
  * CQLSH emits a warning when the server version doesn't match (CASSANDRA-18745)
  * Fix missing speculative retries in tablestats (CASSANDRA-18767)
diff --git a/src/java/org/apache/cassandra/cql3/statements/AlterTypeStatement.java b/src/java/org/apache/cassandra/cql3/statements/AlterTypeStatement.java
index d0e2f33979..c8af0e9dfd 100644
--- a/src/java/org/apache/cassandra/cql3/statements/AlterTypeStatement.java
+++ b/src/java/org/apache/cassandra/cql3/statements/AlterTypeStatement.java
@@ -255,6 +255,12 @@ public abstract class AlterTypeStatement extends SchemaAlteringStatement
 
         protected UserType makeUpdatedType(UserType toUpdate, KeyspaceMetadata ksm) throws InvalidRequestException
         {
+            if (type.isCounter())
+                throw new InvalidRequestException("A user type cannot contain counters");
+
+            if (type.isUDT() && !type.isFrozen())
+                throw new InvalidRequestException("A user type cannot contain non-frozen UDTs");
+
             if (toUpdate.fieldPosition(fieldName) >= 0)
                 throw new InvalidRequestException(String.format("Cannot add new field %s to type %s: a field of the same name already exists", fieldName, name));
 
diff --git a/test/unit/org/apache/cassandra/cql3/CQLTester.java b/test/unit/org/apache/cassandra/cql3/CQLTester.java
index b611a52f53..07504aa5cd 100644
--- a/test/unit/org/apache/cassandra/cql3/CQLTester.java
+++ b/test/unit/org/apache/cassandra/cql3/CQLTester.java
@@ -574,14 +574,20 @@ public abstract class CQLTester
 
     protected String createType(String query)
     {
-        String typeName = "type_" + seqNumber.getAndIncrement();
+        String typeName = createTypeName();
         String fullQuery = String.format(query, KEYSPACE + "." + typeName);
-        types.add(typeName);
         logger.info(fullQuery);
         schemaChange(fullQuery);
         return typeName;
     }
 
+    protected String createTypeName()
+    {
+        String typeName = String.format("type_%02d", seqNumber.getAndIncrement());
+        types.add(typeName);
+        return typeName;
+    }
+
     protected String createFunctionName(String keyspace)
     {
         return String.format("%s.function_%02d", keyspace, seqNumber.getAndIncrement());
diff --git a/test/unit/org/apache/cassandra/cql3/validation/entities/UserTypesTest.java b/test/unit/org/apache/cassandra/cql3/validation/entities/UserTypesTest.java
index 646484c9a1..12a4025e66 100644
--- a/test/unit/org/apache/cassandra/cql3/validation/entities/UserTypesTest.java
+++ b/test/unit/org/apache/cassandra/cql3/validation/entities/UserTypesTest.java
@@ -133,6 +133,10 @@ public class UserTypesTest extends CQLTester
         assertInvalidMessage("A user type cannot contain non-frozen UDTs",
                 "CREATE TYPE " + KEYSPACE + ".wrong (a int, b " + myType + ")");
 
+        String ut1 = createType("CREATE TYPE %s (a int)");
+        assertInvalidMessage("A user type cannot contain non-frozen UDTs",
+                             "ALTER TYPE " + KEYSPACE + "." + ut1 + " ADD b " + myType);
+
         // referencing a UDT in another keyspace
         assertInvalidMessage("Statement on keyspace " + KEYSPACE + " cannot refer to a user type in keyspace otherkeyspace;" +
                              " user types can only be used in the keyspace they are defined in",
@@ -477,6 +481,20 @@ public class UserTypesTest extends CQLTester
         execute("SELECT addresses FROM %s WHERE id = ? ", userID_1);
     }
 
+    @Test
+    public void testCreateTypeWithUndesiredFieldType() throws Throwable
+    {
+        String typeName = createTypeName();
+        assertInvalidMessage("A user type cannot contain counters", "CREATE TYPE " + typeWithKs(typeName) + " (f counter)");
+    }
+
+    @Test
+    public void testAlterTypeWithUndesiredFieldType() throws Throwable
+    {
+        String typeName = createType("CREATE TYPE %s (a int)");
+        assertInvalidMessage("A user type cannot contain counters", "ALTER TYPE " + typeWithKs(typeName) + " ADD f counter");
+    }
+
     /**
      * Test user type test that does a little more nesting,
      * migrated from cql_tests.py:TestCQL.more_user_types_test()