The constancy of fertility levels in Ghana, Senegal and southwest Nigeria since 1970 is separated into its nuptiality and marital fertility elements. The age-specific changes in the two components are examined and these show that the apparent stability in observed total fertility rates is essentially the outcome of the offsetting impact of increased marital fertility below age 25 and above age 40, over the effect of the increasing proportion of women remaining single up to 25 yr of age. Continuity in traditional fertility behaviour and stable nuptiality has remained operative over the broad middle segment of the reproductive lifespan of women in the three areas. The paper thus concludes that West Africa is likely to continue to display stably high fertility for many years into the next century. The social and cultural conditions behind this trend are discussed with special reference to the continued high demand for children and the low and only slowly rising contraceptive prevalence level.