Willingness-to-pay (WTP) techniques are increasingly being used in economic evaluation, as a means of assessing the value of new health care technologies. This paper presents the results of a WTP investigation of two types of screening for colorectal cancer. A questionnaire was issued to a general population via general practitioners (GPs), yielding a sample of approximately 2000 cases for analysis. Regression models demonstrated that WTP was significantly influenced by factors such as gender, income, age, risk perceptions, illness experiences and health beliefs. The median WTP for screening emerged as being pound30 or pound50, depending on the method used to elicit WTP, but independent of the screening protocol. Combining the results with those from related research, it emerged, first, that WTP subjects offered higher values for flexible sigmoidoscopy screening than the costs actually incurred by revealed preference studies and, second, they offered WTP values similar to the likely resource costs of the screening procedures.