A double-blind, placebo, controlled trial was conducted in Banyudono subdistrict, Boyolali regency, Central Java province, Indonesia. The aim of the study was to determine whether adding low-dosage vitamin A and riboflavin can enhance the effect of iron-folate supplementation in anaemic pregnant women. From July to November 2000, 202 pregnant women were screened for anaemia (haemoglobin < 11.0 g/dL). One hundred and three pregnant women (51%) were found to be anaemic and were then allocated alternately into four groups. Over a period of 60 days, group IF (n = 29) received iron-folate tablets (200 mg FeSO4 and 250 microg folic acid) + 5 mg glucose: group IFR (n = 22) received iron-folate tablets + 5 mg riboflavin; group IFA (n = 29) received iron-folate tablets + 2.75 mg retinyl palmitate (equal to 5000 IU vitamin A); and group IFRA (n = 23) received iron-folate tablets + 5 mg riboflavin + 2.75 mg retinyl palmitate. At the end of the study 19 pregnant women (18.4%) were excluded from the analysis because of various reasons. Statistical analysis was based on 84 women (81.5%): group IF, n = 25; group IFR, n = 22; group IFA, n = 18; and group IFRA, n = 19. Haemoglobin measurements were carried out using the Technicon H1* (cyanmethaemoglobin method). All groups showed a significant increase in haemoglobin concentration (P < 0.05), except group IFA (P > 0.05), with the highest increment being in group FR. Multiple comparisons only showed significant differences between group IFR and group IFA (P < 0.05). It can be concluded that iron-folate supplementation can increase haemoglobin concentrations in anaemic pregnant women. Adding riboflavin tends to enhance the effect of iron-folate supplementation, but this is not the case with adding vitamin A.