To clarify the necessity of surgery for fistula-in-ano (FIA) in infant, a retrospective analysis of 82 cases FIA in infant were performed for 11 years period from 1987 to 1998. Group A included 44 cases in the period of surgery oriented treatment to 1992, and group B contained 38, period of feeding control oriented management (FC) after 1993. FC, that was indicated in case with loose stool and eczematoid perianal skin (LSES), composed of quit breast feeding, change of cow milk or complete weaning. Surgical decision was made after improvement of stool condition. Fistulectomy was performed in 29 cases (65.9 %) of group A. However, in group B, only 15 cases (39.5 %) required surgery (p=0.0036). Thirty-four cases in B had the history of LSES, and Fe was applied in 25, and was effective in 24. Among 24 cases, 21 showed complete healing with FC, 3 had surgery because of the persistent FIA, and 1 got operation due to no improvement of stool condition. In conclusion, Fe has to be applied to FIA in infant before surgery, particularly in cases with history of LSES. As one of the etiologic factors for FIA, LSES could be considered to this particular age group.