PURPOSE This study nas undertaken to determine if a community screening program designed to overcome key barriers (lack of awareness, cost of program, ease of access to care) could successfully impact on African-American males knowledge, attitudes, and behaviors regarding prostate cancer screening. The focus of this report is knowledge. To date, there are no reported studies that examine differences in knowledge from a prescreening baseline to a postintervention level for minority participants. PATIENTS AND METHODS A total of 944 men were enrolled in the study in a 20-month period. Prostate screening and education were offered as a new service at an existing senior health clinic. In addition, mass screenings were offered approximately monthly at various locations in the community (including senior community centers, senior apartment complexes, and some public housing projects), Screening included both the digital rectal examination and the prostate specific antigen test. A brief questionnaire was administered during client intake (the pretest) and repeated after the education and screening participation (the posttest). Test items targeted three constructs: (1) etiology, (2) risk status, and (3) clinical factors. RESULTS The largest difference on pretest scores between the racial groups resulted from clinical factor knowledge. African-American men were significantly less likely than Caucasian men to correctly identify early symptoms of prostate cancer acid the basic components of a prostate checkup. Although scores were initially significantly lower for African-American participants, these differences were not evident after program involvement, There was a significant increase in knowledge level for all men when comparing pretest and posttest scores. Significant improvement was noted for each test item, with the exception of one key item, Even after participation in the program, African-American men were still more likely to believe that "pain" was the first symptom of prostate cancer. DISCUSSION An item-by-item analysis revealed that there was only one test item in which program participation did not "correct" knowledge. African-American men were still more likely to believe that pain was the first symptom that would alert them to the presence of cancer. The screening program included information (both printed and oral content) that emphasized the importance of routine screening to detect cancer at an early stage, because most men would experience no symptoms, The only other reported study that examined knowledge documented similar findings with respect to an understanding of symptomology, These findings can be used to direct or guide the educational component of future screening programs that hope to target African-American men.