The epidemiology studies of trichloroethylene (TCE) and perchloroethylene (PCE) as they relate to risk of renal-cell cancer are critically reviewed. The studies fall into two basic groups: cohort studies of workers who use TCE or PCE and community-based case-control studies. Issues of bias, confounding, and chance are examined in relation to the studies. There is little evidence of an increased risk of renal-cell cancer and exposure to TCE or PCE. The few studies with elevations in risk suffer from important methodologic shortcomings. Although it is virtually impossible using epidemiology data to rule out conclusively a small increase in risk of renal-cell cancer, the totality of epidemiologic evidence clearly does not support a causal association with TCE or PCE. Future studies of these chemicals must include quantitative evidence of exposure and proper methodologic design, be large-scale in nature to detect small increases in risk, and provide a coherent interpretation of all epidemiology data on these solvents and risk of renal-cell cancer.