Hi

Select C1 and goto DataValidation Custom Formula: =A1=B1 Remove
mark in "Ignore blanks"

Hopes it helps

Regards,
Per

On 24 Dec., 12:22, Tufail wrote:
hello all,
is there any way to use following as a DataValidation.

IF A1 & B1 is equal then want allow to keying in data otherwise not.

A_1 * B_1 * *C_1
D * * * D * * * Data input ok
D * * * Y * * * Not allow input