Granulocyte-macrophage colony-stimulating factor (GM-CSF) has a stimulating effect on erythroid, megakaryocytic and granulocyte-macrophage progenitors. Activated T lymphocytes, monocytes, fibroblasts and endothelial cells release GM-CSF after stimulation by endotoxin and cytokines such as interleukin-1 (IL-1) and tumor necrosis factor. IL-1 is also released in response to bacterial infections and inflammation by phagocytic mononuclear cells. GM-CSF and IL-1 levels were examined in 10 patients with recurrent pulmonary infection (repeaters) and in 10 patients with acute pulmonary infection (non-repeaters) in the acute and recovery periods of infection. The mean serum GM-CSF and IL-1 levels of non-repeaters were significantly higher than those of repeaters in the acute period of infection (p < 0.002), but the same parameters of both groups were not different in the recovery period (p > 0.05). In addition, both the serum GM-CSF and IL-1 levels of repeaters and non-repeaters in the acute period of infection were higher than those in the recovery period (p < 0.05). There was a positive correlation between serum IL-1 and GM-CSF levels in non-repeaters (r = 0.746, p = 0.013), but no significant correlation between the same parameters in repeaters (r = 0.395, p = 0.259). In this study, we could not explain why the serum GM-CSF and IL-1 levels in repeaters did not increase as they did in non-repeaters; moreover, there was no significant correlation between serum IL-1 and GM-CSF levels in repeaters during the acute period of infection. These findings may be due to microenvironmental factors in bone marrow and/or other factors.