In 1972, cancer registration began in New South Wales (NSW), the most populous state in Australia. The operations of the Registry are described. By 1990, approximately 316,000 new cases of cancer had been notified from a population that had increased from 4.6 to 5.8 million. In 1981-1984, the most common sites in men were lung, prostate, colon, melanoma and bladder, and in women, breast, melanoma, colon, lung and unknown primary site. Cancers which, between 1973-1976 and 1981-1984, had increased in reported incidence by more than 25% were pharynx and kidney in both sexes, rectum, testis and melanoma in men, and lung and bladder in women; those decreasing by more than 10% were stomach in both sexes, oesophagus in men and cervix in women. Age-standardised incidence rates for melanoma (27.4 [m] and 23.8 [f] per 100,000 in 1987) and cancer of the renal pelvis in women (1.7 per 100,000 in 1989) are among the highest in the world.