To test the value of recombinant human granulocyte-macrophage colony stimulating factor for the treatment of delayed engraftment following high dose therapy and autologous hematopoietic stem cell transplantation, we enrolled 12 patients with recurrent non-Hodgkin's lymphoma or Hodgkin's disease having an absolute granulocyte count less than 150 x 10(6)/l on day 30 after autologous hematopoietic stem cell infusion in an open-label, nonrandomized study. These patients were compared to 21 similar historical control patients who were not treated with colony stimulating factor. Overall, the patients treated with granulocyte-macrophage colony stimulating factor had a mean absolute granulocyte count of 704 x 10(6)/l on day 44 after stem cell infusion compared to a mean absolute granulocyte count of 408 x 10(6)/l in historical controls (p = 0.008). The number of documented bacterial and fungal infections occurring after day 30 (9 vs 0, p = 0.01) was significantly reduced in the study group. The toxicity attributed to the granulocyte-macrophage colony stimulating factor was minimal with only one patient experiencing chills. Recombinant human granulocyte-macrophage colony stimulating factor appears to be effective for the treatment of delayed engraftment following high-dose therapy and autologous hematopoietic transplantation for lymphoid malignancies, with most patients having accelerated granulocytic recovery and a reduced incidence of infections.