SQL: Determining your session's transaction isolation level

A question came up from a developer yesterday. He could see how to set a transaction isolation level but didn’t know how to determine the current transaction isolation level. That detail is available in the sys.dm_exec_sessions DMV.

Here’s an example:

SELECT COALESCE(CHOOSE(transaction_isolation_level,
                       'Read Uncommitted',
                       'Read Committed',
                       'Repeatable Read',
                       'Serializable',
                       'Snapshot'),
                'Unspecified') AS CurrentTransactionIsolationLevel
FROM sys.dm_exec_sessions  
WHERE session_id = @@SPID;

2026-06-09