Prostate cancer is one of the most common forms of cancer among American men, and worry about the disease has psychological, behavioral, and biological consequences. To better understand prostate cancer-specific worry, the authors tested a model of the interrelationships among family history of prostate cancer; perceived risk of and worry about prostate cancer; and perceived risk of and worry about other diseases. Men who attended prostate cancer-screening appointments at a general urology practice (n=209) were given a brief anonymous self-report measure. Structural equation modeling (LISREL) results indicated: (1) perceived risk of prostate cancer mediated the relationship between family history of prostate cancer and prostate cancer worry; (2) perceived risk of other diseases increased perceived risk of prostate cancer; and (3) prostate cancer worry and increased other disease worry.