Mortality form stroke in Italy over the period 1955-1987 was analysed in terms of age-specific, age-standardised death certification rates, and by means of a log-linear model to separate the effects of age, cohort of birth and calendar period of death. In males the overall age-adjusted rate on the world standard population fell from 118.4/100,000 population in 1955-1959 to 72.0 in 1985-1987 and in females from 94.8 in 1955-1959 to 54.7 in 1985-1987. The overall decline in age-standardised rates over the 3 decades was thus 39% for males (averaging 1.7%/year) and 42% for females (averaging 1.9%/year). The declines were even greater in truncated rates from 35 to 64 years: from 80.4 to 41.2/100,000 for males (49%), and from 63.0 to 24.1/100,000 for females (62%). Inspection of age-specific rates shows comparable falls--in relative terms--in early and later middle age. For instance, male rates declined from 70.4 to 38.1/100,000 (46%) at age 50-54, and from 1,151.1 to 584.2/100,000 (50%) at age 70-74. Only above age 75 were the falls smaller. In females aged 50-54 years the decline was 63%, and for those aged 70-74 years it was 59%. In young adults, no appreciable changes were observed in either sex. Thus, the age, period and cohort model showed downwards trends in both the period and cohort effect, except for the most recent cohorts on account of an age-cohort interaction. These favourable trends are discussed in relation to better control of hypertension and the potential impact of other risk factors.(ABSTRACT TRUNCATED AT 250 WORDS)