In this paper, we present estimates of national cancer incidence in Portugal in 1996-1998, predictions for the year 2000, and interpret the recent cancer mortality trends in light of observations from epidemiological research and risk factor patterns. In Portugal, national mortality data from vital statistics are available from 1960, while cancer registration has been mandatory since 1988, when three regional cancer registries covering the mainland of the Portuguese Republic were set up. Up until now, however, none of these registries has been able to produce data with an acceptable completeness of registration - hence this study. Mortality data from Portugal for 1996-1998 and incidence data for 1990-1995 from Vila Nova de Gaia (RVNG) (the most complete of the Portuguese cancer registries), 14 Italian registries and nine Spanish registries were assembled to produce the best possible estimates of numbers of incident cases for each age group and gender. A total of 19 880 new cancer cases are estimated to have been diagnosed among men in the year 2000, and nearly 17 000 new cancer cases in women. The most common cancer among Portuguese men in 2000 is cancer of the colorectum (3173 new cases), followed by cancers of the prostate (2973), lung (2611), stomach (2206) and urinary bladder (1360). In women, breast cancer is the most common cancer (4358) followed by cancers of the colorectum (2541), stomach (1494) and corpus uteri (1083). The overall age-standardised cancer mortality rate for men in Portugal increased steeply (1.4% annually) during the period 1988-1998, with prostate cancer (3.6% annually), colon and rectum (3.3%) and lung (2.4%) mostly contributing. Among women, the overall cancer mortality rate was stable (a non-significant decrease of approximately 0.2% per year). These remarkable results, particularly in males, demonstrate the need for a comprehensive national programme against cancer. Since the increasing epidemic of lung cancer (in men), as well as other tobacco-related cancers, is observed in Portugal, the important component of such a programme should be a nationwide tobacco control programme. Improving accessibility to highly effective diagnostic and treatment procedures for cancer in general and colorectal and prostatic cancers in particular should be a priority in the fight against cancer.