Abstract: Based on the data from the survey of 7872 new lyrn aried cnuples who got the marriage 1icenses in two districts of Shanghai from Aug, 1987 to Aug.1988 and were folbwed up to the fifteen month after marriagrl we analyzed cxluples sex preferences for child effect Of sex preference on fertility behavior and factors affectings couples sex preferences More than half of couples( 54.9% of wives and 53.0%of hu shads) had no sex preferent for ch ild 20.9% of wives and 29.3% of husbads desired for boys and 25.9%of wives and 15.6%of hu shads desn'ed for daughter respectlvely T he main reasons for couples preference for a boy were boy is clever and could be cul tivated",to mairs the fan ilylisle and to save my faces by having a sori. Them airs reasons for couples preference for a girl were girl could take care of us when we get older and girl is more elegant and easy to be dressed up". coupies desired for son had higher percentage of desire for children Sex preference had aminor effect on couples fertility behaviorie thewaiting time for conception contraceptive use and fertility Status). The results of multinom ial logisiti regression showed that couples age at marriage, cnuples and their parents education couples occupation household income housing status husband had brother(s) or not and who was the deoision maker for fertility event affected couples sex preferences for child. Evidence indicates. that the further reduction in couples sex preference for child in Shanghai is no of significance in fanmily planning work.