One hundred patients with metastatic carcinoma of unknown primary were analyzed to assess the importance of prognostic factors on survival. Patients were treated with cytostatic combinations, single drugs, or symptomatic care only. Response in the treatment groups ranged from 10% to 33%. The median survival of all patients was 124 days. In a univariate analysis good performance status, the presence of lymph node metastases, and the absence of liver metastases favorably influenced survival. In a Cox proportional hazards model, good performance status contributed significantly to a better survival. In addition there was a trend for female patients, patients with lymph node metastases, and patients without liver metastases to survive longer. These patient subsets deserve optimal treatment despite the dismal prognosis of this disease.