The effect of malaria parasitaemia on spleen size and anaemia in 1,905 pregnant women in Jos Plateau highlands, Bauchi Savannah plains and Ethiope river basin of Nigeria was evaluated. The overall spleen rates in Jos Plateau, Bauchi and Ethiope were 15, 23, 16.33 and 10.71% respectively. Higher cases of palpable spleen were detected in pregnant women than non-pregnant controls. Spleen rates also showed seasonal variation, but not very significant. Malaria prevalence rates were higher than spleen rates. In all three study sites, parasitaemic pregnant women had significantly lower haemoglobin values than malaria negative mothers, especially among primigravids. However, there was no constant association between higher parasite density and splenomegaly, since few cases of enlarged spleens were also recorded among subjects with low parasitaemia. Severe anaemia was predominant among parasitaemic pregnant women with high spleen classes.