During the two-year 1977-1978 period 37 (3.29%) out of 1,124 pediatric surgical wounds became infected in the postoperative course. Ten infections were observed among the 844 "clean" procedures (1.18%), 5/155 "clean-contaminated" (3.22%), 3/32 "contaminated" (9.37%) and 19/93 "dirty" (20.43%). These rates are quite comparable, although somewhat lower, to those found in similar studies carried out in adults. The bacteriologic studies of the contamination and the subsequent infection revealed that "clean" wounds were almost exclusively infected by "Staphilococci", while all the remaining categories (which very often implicated an opening of digestive tract lumen) became infected by multiple endogenous flora including enterobacteriae (mainly "E. coli") and anaerobic germs ("Bacteroides" and "Clostridia"). The limited use of antibiotics in this series was guided by these bacteriologic findings, a fact that can partially explain our results. There was no mortality directly related to the infection of the wound, but the risks and uncomfort incurred by the patients were not negligible and must be taken into consideration aside with the increase of the cost of hospital stay (evaluated as 35,000-100,000 ptas./patient in this series) to justify every effort to decrease incidence of this generally minor complication.