The risk of cancer was analysed in a cohort of 20,245 licensed pesticide applicators in agriculture who had licences issued between 1965 and 1976. Most were men (99%) and about 50% had been born in 1935 or later. The cohort was followed up in the Swedish Cancer Register from date of licence until death or 31 December 1982. The mean follow up time was 12.2 years. Average time since first exposure was longer, however, since one fifth of the cohort was exposed in the 1950s. A total of 558 malignant tumours was found compared with 649.8 expected, which resulted in a statistically significantly decreased standardised incidence ratio (SIR) of 0.86 (95% confidence interval (CI): 0.79-0.93). Significantly decreased risks of cancer were also found for liver (SIR = 0.45, 95% CI: 0.18-0.93), pancreas (SIR = 0.50, 95% CI: 0.26-0.87), lung (SIR = 0.50, 95% CI: 0.35-0.68), and kidney (SIR = 0.53, 95% CI: 0.32-0.84). No statistically significantly increased risks or any time trends were observed. SIR for testicular cancer was increased (SIR = 1.55, 95% CI: 0.92-2.45) and increased with period since licence. Eighteen cases with testicular cancer were found. For those born in 1935 or later a non-significant increased overall risk of cancer was observed (SIR = 1.07, 95% CI: 0.82-1.37). Comparisons were made with agricultural workers in general since pesticide applicators are mainly farmers that use or have used pesticides to a greater extent. Higher risks for pesticide applicators were found for testicular cancer, tumours of the nervous system and endocrine glands, and Hodgkin's disease.