Summary: In this study, we compared the growth, health, behavior, and economics of feeding dairy calves organic milk replacer or whole milk during the preweaning period. Calves fed organic milk replacer had similar growth to calves fed organic whole milk. Milk feed cost was 37% lower for calves fed organic whole milk. The average cost per kilogram of gain was lower for calves fed organic whole milk compared with calves fed organic milk replacer. Organic dairy producers may find economic advantages of feeding whole milk to organic dairy heifer calves during the preweaning period compared with organic milk replacer because of the high cost.