Objective: To evaluate the bioavailability of iron in fortified baby food (porridge), using the "in vivo" method in Holtzman rats without anemia. Methods: Randomized and controlled experimental design. 48 rats of the Holtzman strain without anemia were used, which were assigned for 10 days to 4 types of diet: Group 1 (Porridge A), Group 2 (Porridge B), Group 3 (Casein with iron) and Group 4 (Casein without iron). The animals were placed in individual metabolic cages to determine the consumption of diet and excreta on a daily basis. Iron bioavailability was determined through metabolic balance, apparent digestibility coefficient, and iron retention percentage. Results: Food consumption, weight gain, iron intake and fecal iron excretion were significantly higher in the groups with a porridge-based diet (p <0.05) compared to the casein groups, the metabolic balance of iron, digestibility coefficient and iron retention percentage were negative in the porridge and casein groups without iron, while the casein group with iron showed a positive balance of iron in the 3 indicators, these differences were significant (p <0, 05). Conclusions: The porridge-based diets showed lower bioavailability of iron compared to the casein diet with iron, which would indicate that the inputs used in the formulation of the porridges could be affecting the absorption of iron.