The effects of the addition of color to a dry primate diet on the feeding behavior of orangutans were studied. Purina Monkey Chow was dipped in food coloring (red, green, blue, orange). Colored and plain chow was offered to the subjects, three adults, and two juveniles. Time to eat or lose interest in feeding, quantity, and color of pieces of chow handled and eaten were recorded for each group. The juveniles' consumption of chow increased when offered colored chow, and adults required less time to consume their food. One juvenile showed a significant preference for red monkey chow.