If your undo tablespace has grown to a large size and you need to recreate it , you can do so with the following easy steps: STEP 1: Query V$PARAMETER to see the default UNDO tablespace currently active. SELECT name,value FROM v$parameter WHERE name IN ('undo_management','undo_tablespace'); NAME VALUE _______________________ undo_management AUTO undo_tablespace UNDOTBS2 STEP 2: Create a new tablespace that will be the new default tablespace. CREATE UNDO TABLESPACE undotbs02 DATAFILE '/oradata/oracle/oradata/DB1/undotbs02.dbf' SIZE 500M REUSE AUTOEXTEND ON NEXT 4096K MAXSIZE 10240M; STEP 3: Set this newly created UNDO tablespace to default UNDO tablespace. ALTER SYSTEM SET undo_tablespace = 'UNDOTBS02'; STEP 4: Set the old tablespace to OFFLINE to be eligible to drop. ALTER TABLESPACE undotbs2 OFFLINE; STEP 5: Drop the old UNDO tablespace. DROP TABLESPACE undotbs2 INCLUDING CONTENTS AND DATAFILES; ------------------------