Twofold to threefold increases in risk for colorectal cancer associated with pattern and model making in the automobile industry have been suggested by several reports. This paper reports the investigation of a cohort of 7545 General Motors pattern and model makers originally defined for the purpose of cancer screening. All-cause mortality for this cohort was lower than that of the US population (standardized mortality ratio [SMR] = 0.7; 95% confidence limits 0.6, 0.8). There were 22 colon cancer deaths v 10.9 expected, resulting in a significantly elevated SMR of 2.0 (95% confidence limits of 1.3, 3.0), consistent with previous studies. The colon cancer SMR for nonparticipants in the screening programs was 4.0 (95% confidence limits of 2.2, 6.7), emphasizing the importance of complete follow-up for all members of a defined cohort.