The results and complications of 224 marrow collections from 200 patients with malignant disease who underwent marrow aspiration and storage for subsequent autologous marrow transplantation (AMT) were analyzed. The median age of the patients was 35 years (range 1-68); 131 patients had hematologic malignancies and 69 had solid tumors. Thirty-one patients proceeded directly to AMT after marrow aspiration at a median of 4.5 days (range 0-10). A further 75 patients received AMT a median of 3.0 months (12 days-10 years) after marrow aspiration. The remaining 94 patients had marrow stored but not infused. When a second aspiration was performed from the same patient within seven weeks, the yield of marrow nucleated cells was significantly reduced (p less than 0.02). A negative linear correlation was observed between CFU-C/kg harvested and the day to achieve a posttransplant blood neutrophil count greater than 500/cmm (r = -0.3092, p less than 0.05). A total of 36 (17.4%) complications associated with marrow aspiration were observed including two (0.97%) life-threatening episodes. Postoperative fever accounted for 23 of 34 episodes of minor complications. There was no increased risk of serious complications with decreased time from aspiration to transplant. It was concluded that the morbidity and mortality from autologous marrow aspiration did not differ significantly from that observed in normal donors.