To evaluate the professional practices of physicians in Antananarivo in managing acute diarrhea in infants. This prospective study was conducted from March 19 to April 21, 2012, as an anonymous survey of randomly selected general practitioners and pediatricians working in the public or private sector in the city of Antananarivo. The survey included 125 physicians: 105 general practitioners, 11 pediatricians, and 9 other specialist physicians (7.2%) with pediatric activity. Only 4.8% of the physicians questioned had not received training about diarrhea in the previous two years. One doctor in 4 (25.6%) did not prescribe oral rehydration solution. The reasons given were lack of signs of dehydration (50%) and recommendation of other beverages (15.5%). Zinc prescription was rare (9.6%). Early refeeding was recommended by 41.6% of physicians. Almost half (47.2%) routinely use antibiotics, and 86.4% prescribe antidiarrheal medications. The WHO recommendations for the treatment of acute diarrhea in children are not followed. Continuing and repeated medical education is necessary.