The overall aims of the study were to determine the prevalence of anaemia in women of reproductive age and to investigate the underlying causes, as well as assess the effectiveness of antenatal care (ANC) interventions for anaemia prevention. Consecutive pregnant women booking for ANC (n=2235) were screened for anaemia, followed up and screened again late in pregnancy. Basic ANC interventions included iron and folate supplementation, malaria chemoprophylaxis and referral of severe anaemia cases, and in addition staff training and education for the women and the community at the study clinic. Non-pregnant women (n=504), adolescents: pregnant (n=76), non-pregnant (n=130), and boys (n=101) were also screened for anaemia. Haematological and biochemical investigations were made on anaemic cases. The prevalences of anaemia and severe anaemia in pregnant women were 60% and 3.8%, respectively. The adolescent pregnant women were more anaemic, with an overall prevalence of anaemia of 76%. In the non-pregnant women the prevalence was 49%. Anaemia was more prevalent in adolescent girls than in boys, and iron deficiency was the main underlying cause in all groups. In the anaemic pregnant women, malaria and other infections were more common, and Serum ferritin therefore underestimates iron deficiency. ANC interventions achieved a significant reduction in the prevalence of severe and moderate anaemia but only a moderate reduction in overall prevalence of anaemia. Time for treatment of anaemia during pregnancy is inadequate to correct pre-existing nutritional deficiencies, and all the underlying factors are not addressed. Anaemia control must include all women of reproductive age, starting with adolescents to build up their iron stores before pregnancy. ANC supplementation should include other nutrients, and there is also a need to identify and treat infections during pregnancy. Training of ANC providers and supervision as well as improvement in the logistics and supply supplements to the clinics needs reinforcement.