Assuming that all the IF statements are mutually exclusive and lnBalance gets only one result, it appears to me that you could have one IF-ELSE statement based on lnAcno. You could then put a DO CASE statement in each block . Arrange the CASE statements so that the most likely ones are first to be tested.

IF lnAcno = acno
     DO CASE
          CASE < test one >
               lnBalance = 0
          CASE < test two >
               lnBalance = lnMbalance
          CASE < test three > 
                etc.
     ENDCASE
ELSE
     DO CASE
          CASE < test one >
             etc
     ENDCASE
ENDIF

>All my tables are properly indexed.But there are several if conditions.I think these checkings are slowing my prg but they are obvious.
>
>Here is my code:
>
>

>
>if  month(date)<month(Mdate) AND lnAcno=acno  AND year(Mdate)=year(date)
>lnBalance=0
>endif
>
>if  lnAcno=acno  AND year(Mdate)>year(date) and lnBalance=0 and month(date)<month(Mdate)+12
>lnBalance=lnMbalance
>endif
>if  lnAcno=acno  and  MONTH(date)=MONTH(Mdate)  and  day(date)<=10  and year(Mdate)=year(date)
>
>lnBalance=lnBbalance
>endif
>
>*** so many
>
>

>
>How I can change my code to speed it up.If you allow I can send the code to you via email.
>
>Chandan