To investigate the efficacy of two different iron supplements administered either on a weekly basis or during menstruation, a 16-week community experimental study was carried out among postmenarcheal female adolescent students in Kupang, East Nusa Tenggara, Indonesia. Forty eight students received a placebo tablet weekly, 48 other students got an iron tablet weekly and 41 students took an iron tablet for four consecutive days during their menstruation cycle. All subjects were given deworming tablets before supplementation. Haemoglobin, serum ferritin, height, weight, mid-upper arm circumference and dietary intake were assessed before and after intervention. The supplementation contributed to a significant improvement in the iron status of the intervention groups compared to the placebo group (P < 0.05). In the menstruation group, the haemoglobin concentrations of the anaemic subjects improved significantly (P < 0.05) while for the non-anaemic subjects, serum ferritin concentrations also increased significantly (P < 0.05). In the weekly group for anaemic and nonanaemic subjects, there was a significant increase in both haemoglobin and serum ferritin concentrations (P < 0.05). This study revealed that weekly supplementation of iron tablets continued for 16 weeks contributed a higher improvement to haemoglobin concentration, compared with supplementing iron tablets for four consecutive days during menstruation for four menstrual cycles. This suggests that weekly iron supplementation is preferable.