A retrospective descriptive study on the relative frequency of surgical site infection (SSI) among 235 operated cancer patients at Chong Hua Hospital was done covering the period from January 1991 up to May 1993. SSI occurred in 9.4 percent (22/235). There was a significant increase in SSI as the population became older (p=0.01). Dirty operations had a significantly higher infection rate of 50 percent (2/4) compared to 8.7 percent (20/211) for the rest (p=0.45). Clean operations had a significantly lower infection rate of 2.5 percent (3/121) compared to 16.7 percent (19/114) for the rest. There was no difference in SSI between early and late stage cancer cases. Operations in the alimentary tract had a significantly higher infection rate of 19.3 percent (11/57) compared to 6.4 percent (11/172) for operations on the other sites (p=0.004). Operations on solf tissues, breast and thyroid had a signifanctly lower rate of 4.6 percent (4/87) compared to 12.7 percent (18/142) for operations on other sites (p=0.045).(Author)