PURPOSE To determine effectiveness of prophylactic antibiotics in preventing cholangitis, we conducted a systematic review comparing cholangitis occurrence in biliary atresia patients after Kasai portoenterostomy (KP) with and without antibiotics. METHODS We searched online bibliographic databases from April 1, 2013, using search terms "biliary atresia" OR "cholangitis" AND "antibiotics," selecting studies with control group data. RESULTS Four of 509 titles met inclusion criteria, yielding a total of 319 patients from 3 countries. Three studies were retrospective cohorts and one was a randomized clinical trial. Two cohort studies concluded that prophylactic antibiotics reduced incidence of cholangitis and one did not. The randomized clinical trial supported prophylaxis after comparing the prospective randomized groups to a historical control group. CONCLUSION Few published studies measure the effect of prophylactic antibiotics after Kasai portoenterostomy. We identified 4 studies and they presented contradictory results. Prospective research is needed.