Although en bloc resection for contiguous invasion by adenocarcinoma of the colon is a well-recognized principle, it is difficult to assess the efficacy of this principle when upper abdominal viscera are involved. This study was undertaken to better define this subgroup. Seventeen patients were studied over a period of 20 years who underwent extended resections for colonic adenocarcinoma with upper abdominal organ invasion. The age range was 30 to 81 years (average, 61 years). There was a male-to-female ratio of greater than 2:1. The duration of presenting symptoms was as short as 4 days and as long as 18 months (average, 4.3 months). The most common complaint was weight loss (13/17). The next most common complaints were abdominal pain (10/17), bowel complaints (5/17), and septic symptoms (4/17). A single organ was involved in 7 instances, but multiple organs were involved in most cases. The frequency of involvement was the stomach, spleen, and duodenum (5 each), abdominal wall and diaphragm (4 each), pancreas and liver (3 each). There were 2 perioperative deaths and 9 other major complications. The most common cause of morbidity and mortality was septic in nature in 8 of the 11 instances. All 3 patients with pancreatic resections had postoperative complications; none were fatal. Five patients survived over 10 years, three were 5-year survivors, and two are living and free of disease at less than 5 years. Excluding the two perioperative deaths, four of the five patients who died in less than 5 years had documented recurrences.