Mobile screening mammography was offered to 3,627 employees of a large corporation in Pennsylvania and Delaware. The examination was available to women employees or employee spouses aged 35 years and older. Women were charged $30 for a standard two-view examination. They also received health education materials on mammography and breast self-examination. The remaining costs of the program were underwritten by the corporation. During this program, 3,627 mammographic studies were performed; 63 biopsies were recommended. Fifty-seven biopsies were performed, and nine cancers were diagnosed. Costs of this program are presented in detail. The authors conclude that mobile screening programs at the work site provide an inexpensive, convenient alternative to more traditional screening programs. The inherent advantages of this program are the low cost, the relative ease with which the examination can be performed, and the positive role that corporate medical personnel assume in encouraging individual and group participation.