The cost-effectiveness of a series of mutually exclusive colorectal cancer screening programmes with varying screening interval and target group are analysed. Costs and effects for 60 possible screening programmes are simulated on the basis of data collected from a randomized trial initiated in 1985 in Funen County, Denmark. The screening test applied is the unhydrated Hemoccult-II. The analysis identifies six efficient programmes with cost-effectiveness estimates ranging from 17000 to 42500 Danish kroner (DKK) per life-year.