This works also:

DECLARE @test1 TABLE (Field1 varchar(1), Field2 int);

INSERT INTO @test1

SELECT 'A',1 UNION

SELECT 'B',2 UNION

SELECT 'C',3 ;

DECLARE @Test2 TABLE (Field1 varchar(1), Field2 int);

INSERT INTO @Test2

SELECT 'B',2 UNION

SELECT 'C',3 ;

select * from @test1 t1

where not exists(select 1 from @Test2 t2 where t1.Field1 = t2.Field1 and t1.Field2 = t2.Field2);