Try Data=Validation

Select column (in this example it is A)

Allow: Custom

Formula is: =COUNTIF(A:A,A1)=1

Add your message in the "Error Alert" tab

HTH



"adeel via OfficeKB.com" wrote:

On my work place I maintain record which have Sr. Codes, every time I enter
new record I enter New Sr. Code. please tell me some way that duplicate Codes
not enter. if i try to enter code which I have already enter the error
message come which prompt me for duplicate entry.

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