The purpose of this study was to assess possible regional disparities in the management of colon cancer in France. In 1995, 1605 patients with a colon cancer in eight areas covered by a population-based cancer registry were studied. Pre-therapeutic work-up, stage at diagnosis and therapeutic modalities were assessed. There were no differences between areas concerning the resection or the stage at diagnosis. The proportion of patients with a colonoscopy alone varied between 42.7 and 70.4% (P<0.001). The use of both colonoscopy and barium enema was even more heterogeneous (extremes from 11.7 to 40.2%, P<0.001). There were significant differences in the performance of abdominal computed tomography and tumour markers. The number of examined lymph nodes was lower than the recommendation in 47.3% of cases with extremes ranging from 36.9 to 60.9%. Adjuvant chemotherapy was performed on average in 49.4% of cases in stage II (in which it is not recommended) with extremes from 18.8 to 72.5% (P<0.001) and in 79.6% of the cases in stage III (in which it is recommended) with extremes from 63.6 to 94.4% (P=0.08). In conclusion, these results should alert practitioners and health care authorities in order to homogenize practices.