This study aimed to evaluate survival in 2,339 colorectal cancer patients diagnosed in 1985–87 in the province of Florence, where the Tuscany Tumour Registry is active. The effect of sex, site (colon, rectum), sub-site, disease diffusion (localized, regional, distant, unspecified), year of diagnosis, place of residence (municipalities involved in the screening programme, Florence, others) and source of diagnosis (Center for the Study and Prevention of Cancer—CSPO, others) were evaluated. Five-year observed and relative survivals were 37.9 and 48.1% respectively. Five-year prognosis was worse in men, in older age groups, in advanced stages and in patients not diagnosed at the CSPO. No differences were shown in residents of municipalities involved in the screening programme. Relative 5-year survival in Florence was among the highest in Europe for cancers of both the colon and the rectum. Sex, age, disease diffusion and source of diagnosis showed an independent prognostic effect. The effect of screening was not evident, probably due to the low compliance during the period under study and to the use of a low sensitivity test.