Haematological values were studied in 495 apparently healthy pregnant Nigerian women receiving antenatal care in a maternity hospital in Ibadan, Nigeria. Means, standard deviations and ranges of haematrocrit, total and differential white cell counts, absolute platelet count, erythrocyte sedimentation rte, prothrombin time (PT) and partial thromboplastin time (PTTk) were determined. The mean haematrocrit was 0.311 (SD 0.033), mean total leucocyte count was 5.765 x 10(9)/L (SD 1.753 x 10(9)/L) and mean platelet count was 193 x 10(9)/L (SD 46 x 10(9)/L). The mean erythrocyte sedimentation rate was 18.6 (SD 7.4) mm/hour, mean prothrombin time was 12.3 (SD 2.5) seconds and mean partial thromboplastin time was 38.4 (SD 2.0) seconds. There were significant differences between the second and third trimesters of pregnancy in nay of the haematological values studied. The study has presented the range of variations in haematological values (including those that measure coagulation) in apparently healthy pregnant Nigerian women. It would appear that in the population studied, there were no significant differences in these haematological values between the second and third trimesters in otherwise healthy women receiving regular antenatal care.