The total fertility rate (TFR) in Pakistan ranged between 6.0 to 5.4 and the crude birth rate between 42 to 34 in the early 1970s. An attempt was made to decompose the TFRs using the Bongaarts model and data obtained in the Pakistan Fertility Survey/PFS (1974-75), the Pakistan Contraceptive Prevalence Survey/PCPS (1984-85), the Pakistan Demographic and Health Survey/PDHS (1990-91), and the Population and Family Planning Indicators Survey/PFPI (1993). There was a decline of 4% in the crude birth rate between the PFS and the PCPS and 2.6% between PCPS and PFPI. The age specific fertility rates produced TFRs of 6.3, 6.0, 5.4, and 5.38 births per woman in the respective surveys. The PFS indicated that 98% of women were married by the time they reached the age of 35-39. The age at first marriage also showed a rising trend during this period of 19 years. Women with no education married 4 years earlier than women with secondary or higher education according to a 1984 study. Contraceptive prevalence also increased considerably during this period. 20.7% of currently married nonpregnant women used modern methods and 4.7% used traditional methods in 1993. Contraceptive prevalence increased from 5.2% according to the PFS to 25.4% according to the PFPI. Pakistani mothers breastfed their children for 16.5 months, 18.5 months, and 19.5 months according to the PFS, PCPS, and PDHS. Utilizing a model developed by Bongaarts the effects of 4 most significant proximate determinants of fertility were assessed for the period of 1974-93. These were marriage, contraceptive use, abortion, and postpartum infecundability. The fertility-inhibiting effect of lactational infecundability was the most significant in all 4 surveys, followed by the effect of proportion of women married, while contraception was the least significant determinant of TFR. Lactational infecundability reduced fertility to about 32-37%. The fertility-inhibiting effect of age at first marriage increased from 22% to 33% during this period of 19 years.