We studied if the fecal fat concentration as measured by the near infrared reflectance analysis in a spot sample is an acceptable screening test for malabsorption. This measurement was compared with the more complex fat balance in 120 patients with a suspected malabsorption [53 with chronic pancreatic disorders (CP), 67 with other digestive disorders (nCP)]. The fecal fat concentration proved to be well correlated with steatorrhea in CP (r = 0.86) but not in nCP (r = 0.35). A fat concentration of 9 g% had a sensitivity and a specificity for steatorrhea of 88.8% and of 97.1% in CP, but only of 53.8% and of 94.4% respectively in nCP. The fecal fat concentration was significantly higher in CP than in nCP, even considering patients with steatorrhea only; however, the overlap between the two groups was too high to suggest a clinical usefulness of this test in the differential diagnosis of steatorrheas. It is concluded that the fat concentration in a small sample, easily obtained also in outpatients, is useful in the selection of patients with chronic pancreatitis to submit to a proper fat balance study.