Although cancer screening has been introduced into physical checkup programs in the workplace, it has not been regulated by the Occupational Health and Safety Law in Japan. In addition, the target age groups and strategy for cancer screening have not been defined. To aid in development of better screening programs, we investigated primary factors considered for introducing cancer screening in workplaces. A mail survey targeted 441 facilities of the Kanto Occupational Health Management Association in June 2002. We received ninety-one responses (20.6%), including 59 facilities of manufacturing companies. The implementations of gastric and colorectal cancer screening were higher than other cancer screenings, exceeding 90% in the responding facilities. Thirty years old or over was the target age in most facilities. The facilities were divided into two groups, A and B, except for two examples whose strategies for cancer screening were not well-documented in their response. There were 35 facilities in group A and 54 in group B. In group A, cancer screening was conducted using strategies for all of which effectiveness has been established. On the other hand, in group B, cancer screening was conducted using strategies whose effectiveness were at least partially unestablished. We chose five items to evaluate important factors for introducing a cancer screening program into the workplace: prevalence, screening strategy, effectiveness, efficacy and needs of workers. The most important was the same in both groups, effectiveness. However, there was a tendency for neglect of this aspect in actual conducted plans. Appropriate cancer screening should be carefully coordinated in accordance with the guidelines of the Task Force for Cancer Screening in Japan in the workplace.