The impact of contamination on wound infections was investigated in 120 patients undergoing appendicectomy for appendicitis. A quantitative sample for culture of enterobacteria was obtained from the subcutaneous wound with the velvet pad imprint technique. Average number of enterobacteria (CFU) in the would was 1.2 logarithms higher in operations for gangrenous appendices and 2.3 logarithms higher in perforated appendices compared to flegmonous appendices. Infection rate was 2.5% in flegmonous, 10% in gangrenous and 27.5% in perforated appendices. The results focus the close relation between contamination and subsequent infection.