Hi
It could be that although the cell format is showing those cells as
21:00, the underlying value might be 21:00:01.
Try
=TIME(HOUR(Sheet1!A1),MINUTE(Sheet1!A1),0)=TIME(HOUR(Sheet2!A1),MINUTE(Sheet2!A1),0)

Signature
Regards
Roger Govier
>i ve list of time like that 18:20 , 18:40, 19:00 changing every 20
> minutes. theese are column heads. and now i want to call these datas
> under time columns compare with same time another sheet.
> it works with all other times except 21:00, 03:00, 06:00.
>
> i tried every kind of format but it doesnt resulted . please help me