OBJECTIVE: •To investigate the incidence of carcinoma of the prostate (CaP) in Sri Lanka and compare the rates with the migrant population in the UK. METHODS: •The Sri Lanka cancer registry data were used to determine the rates of CaP in Sri Lanka from 2001 to 2005. •The incidence of CaP in 8,426,000 men, aged ≥30 years, was analysed using 5-year age bands and age-standardized rates were calculated using European standard population data. •The relative risk was calculated by comparison with the South Asian migrant population in the UK using the Prostate Cancer in Ethnic Subgroups (PROCESS) study data, a population-based retrospective cohort study of 2140 men carried out over a 5-year period in four predefined areas of southern England. •Data from incidental findings of CaP in Sri Lanka on transurethral resection of the prostate (TURP) specimens were also analysed. RESULTS: •In all, 1378 new cases of CaP were diagnosed during the 5-year period with a mean age of 69.2 years at diagnosis. •Compared with the previous 5 years, the incidence of CaP had doubled to 5.7 per 100,000, but was significantly lower than in the PROCESS study (relative risk 0.25). •Districts with a higher population density had higher adjusted rates of CaP in Sri Lanka (5.8-12.4 per 100,000). •For TURP specimens, 16.8-18.75% had incidental diagnoses of CaP in Sri Lanka, higher than other published studies. CONCLUSIONS: •The Sri Lankan cancer registry data showed a low rate of CaP, similar to other South Asian countries, but the actual incidence of CaP in Sri Lanka is probably higher than reported, as seen in the densely populated districts and the high rate of incidental diagnosis of CaP in TURP specimens. •The incidence of CaP in migrant South Asians in the UK was much higher than in Sri Lanka. •Further studies are required to examine the environmental and genetic components which may be responsible for the low incidence of CaP in Sri Lanka.