Between April 1987 and July 1988, 44 adults with histologically proven, objectively assessable advanced nonosseous sarcomas were treated with 2.5 g of ifosfamide/m2, 100 mg of etoposide/m2, and 2.5 g of mesna/m2 (500 mg/m2 X 5) daily for 3 consecutive days every 4 weeks. This regimen was generally well tolerated as outpatient treatment. Because of the potential CNS effects of ifosfamide, we recommended that elderly patients, persons receiving high doses of opiates, and patients susceptible to the syndrome of vertigo, perspiration, and hypotension (without tachycardia) be hospitalized for treatment. At initial treatment, leukocyte count nadirs were less than 1,000/microL and platelet count nadirs were less than 100,000/microL in 38% and 15%, respectively, of the 39 patients for whom such data were available. Objective tumor regression occurred in approximately 16% (95% confidence interval, 7%-30%) of the 44 patients (six, partial responses; one, complete response). For the 44 patients, median time to disease progression was 2.3 months; median time to death was 9.4 months. While this regimen was effective in three of 20 patients who had been previously treated with a doxorubicin-based regimen, only one of the 12 patients whose tumors had been primarily refractory to the doxorubicin-based regimen experienced objective tumor regression on our ifosfamide-based regimen.