Food fortification is an important long-term strategy for addressing micronutrient deficiencies. Finding the ideal Fe fortification compound, however, remains a challenge. In the present study the effect of ferrous bisglycinate as fortificant in brown bread was compared with that of electrolytic Fe among Fe-deficient school children in a randomised controlled trial. Children (n 160), aged 6-11 years, with serum ferritin <20 microg/l, were randomly assigned to one of three treatment categories: (i) standard unfortified bread; (ii) bread with electrolytic Fe as fortificant; and (iii) bread with ferrous bisglycinate as fortificant. Each child received four slices of bread (120 g) on school days, which supplied an average of 3.66 mg elemental Fe per intervention day for 137 d (2.52 mg/d for 75 d and 5.04 mg/d for 62 d) over a period of 7.5 months. Hb, serum ferritin, serum Fe and transferrin saturation were measured at baseline and at the end of the intervention. Significant treatment effects were observed for Hb (P = 0.013), serum Fe (P = 0.041) and transferrin saturation (P = 0.042) in the ferrous bisglycinate group, but not in the electrolytic Fe group. There were no significant intervention effects for serum ferritin in either treatment group. Overall, ferrous bisglycinate as Fe fortificant in brown bread performed better than electrolytic Fe in a group of Fe-deficient school children over a period of 7.5 months.