The recruitment experience is described for a large multicenter clinical trial, the Lung Health Study, which required the screening of more than 73,000 male and female smokers aged 35-60. This paper summarizes the plans, methods, and recruiting experience of the 10 participating clinical centers. Recruitment proposals were prepared by each clinical center as part of the contract application process. Recruitment directors and staff were appointed whose primary responsibility was recruitment. Only one clinical center retained its original plan throughout; most clinical centers achieved their recruitment goals by supplementing their originally proposed strategies with one or more methods. The most frequently used methods were worksite, public site, mass mail, telephone, media, and referral strategies. The most significant contributions to the success of the recruitment process were the willingness and initiative of the clinical centers' staff to explore alternative techniques that would take advantage of local circumstances and their ability to incorporate as many workable recruitment methods as necessary to achieve the goal.