Genetic groups of Holsteins selected for large size or small size were compared for health care needs. Two groups were formed from a paired foundation population. Large group was mated to sires with extreme estimates of transmitting ability for tall height and deep and wide bodies. Small group was similarly mated to extreme sires but to those transmitting short height and shallow and narrow bodies. Predicted Differences for milk and fat of sires were above breed average. Actual expenses for veterinary treatment, health supplies and drugs, and value of labor required of animal attendants were evaluated. Large cows required significantly more health care than small cows. Digestive disorders accounted for much of the group difference, and displaced abomasums were more frequent among large cows. Small cows may have economic advantages over large cows of the same breed.