This report presents the first findings of the Murcia Cancer Registry, a population-based cancer registry set up in May 1981 in the Murcia region of southeast Spain (955,487 inhabitants). Descriptive epidemiological methods have been applied to study cancer incidence in 1982. The validity of cancer registration has been assessed for both completeness and accuracy. Altogether 1,987 cases were registered in 1982, the crude (all-ages) annual incidence rates per 100,000 being 238 in males and 179 in females. Excluding nonmelanoma skin cancer, which seems to be incompletely registered, age-standardized rates for Murcia are very similar t o those of other registries in Spain in males, but lower in females. The risk was higher in males than in females for all sites and for the great majority of specific sites, especially larynx, oesophagus and bladder. The age-standardized rate for cancer of the larynx was 26 times higher in men than in women. Lung cancer was the most common cancer in males: the risk was 8 times that in females. Lung cancer rates were higher, in both males and females, than in other Spanish registries. Cancer of the larynx was the second most common site in males when either truncated rates (35-64 years) or cumulative incidence rates up to 64 years of age were used. The age-standardized rate (I8 per 100,000) supports previous studies suggesting that the risk for this cancer in Spain and other Mediterranean countries is very high. The lung/laqhx rate ratio in men was two. Cancer of the breast i s the most common cancer among women, as in other registries in Spain and in most other countries. The age-standardized rate (29.4 per 100,000) is lower than breast cancer rates elsewhere in Spain. This difference may be partly explained by incompleteness of ascertainment in Murcia. The incidence rate for cancer of the cervix uteri was 4.9 per 100,000, excluding carcinoma in situ. Despite the limitations of the data, cervical cancer incidence in Murcia is likely to be similar to that in other regions of Spain. 4T0 whom reprint requests should be sent. 'The following people comprise the Scientific Advisory Committee of the Murcia Cancer Registry: A.