The authors performed a principal components factor analysis on the 18-item Brief Symptom Inventory (BSI-18), a new brief screening inventory. The factor analysis, in which four factors were specified, is consistent with findings in a previous community sample. The study sample consisted of 1,543 cancer patients who completed the full BSI as part of their entry into care at a regional cancer center. The reliability of the BSI-18 was determined based on the calculation of the internal consistency, mean item scores, and correlations with the total score of the BSI. In addition, sensitivity and specificity was calculated to determine the ability of the BSI-18 to discriminate positive and negative cases. The BSI-18 is a shortened version of the BSI that can serve as a brief psychological screening instrument. The BSI-18 can be incorporated into outpatient clinics to prospectively and rapidly identify cancer patients with elevated levels of distress who are in need of clinical interventions. Early identification of distress with appropriate interventions can reduce distress, enhance quality of life, and decrease health care costs.