We assessed the nutritional status of general surgery patients with and without cancer from a western European population in this prospective study. Anamnestic (weight development, abdominal complaints) and anthropometric (fat tissue measurements) data were collected on six groups of patients: cancer of the stomach (n = 13), pancreas (n = 13), colorectal (n = 23), breast (n = 12), and two control groups with benign diseases, ages 20-45 and 50-75 y. From these data, body mass index and ideal body weight were calculated. Concentrations of albumin, transferrin, retinol-binding protein, prealbumin, and creatinine height index were determined by biochemical tests. A weight loss of more than 10% was found in only 31% of gastric and 61% of pancreatic cancer patients. Significant values from anthropometric data were also found only in these groups. In biochemical tests, only the creatinine height index was reduced in all patients with pancreatic cancer. The remaining laboratory changes were so unspecific in all other parameters that no conclusions could be drawn as to the status of the patient's nutritional condition. For the evaluation of nutritional status, only relatively simple and inexpensive anamnestic and anthropometric measurements are necessary.