This study was designed to determine whether gastric acidity, added phytate or iron status significantly influenced the effects that dietary proteins have on iron absorption. Rats were fed test meals of wheat cereal, with and without an added dietary protein (beef, pork, chicken, fish or egg white), by gavage. The influences of phytate and gastric acid were investigated by adding sodium phytate to the test meals and by treating the rats with cimetidine to inhibit gastric acid production. Iron status was altered by dietary regimens. Significant (P < 0.05) effects of the proteins were determined by comparison of the various protein-containing meals to control meals of cereal or cereal + phytate, as appropriate. Gastric acidity, phytate and iron status were all confirmed as factors significantly affecting iron absorption. Beef, pork and chicken enhanced iron absorption, but only when phytate had been added to the meals and only in iron-deficient rats. Enhancement by meat was sufficient to overcome the inhibition by phytate. Fish was an inhibitor or enhancer in cimetidine-treated, iron-deficient rats, depending on the absence or presence of phytate, respectively. Egg white inhibited absorption from cereal meals in cimetidine-treated, iron-deficient rats.