The accurate diagnosis of the indeterminate pulmonary infiltration remains a difficult clinical and pathological problem. The increased use of pulmonary biopsy and resection has, in many instances, led to the correct diagnosis. However, in many other clinically similar cases, the exact diagnosis sill remains obscure even after biopsy. The purpose of this report is to analyze 23 cases of granuloma of the lung that presented as indeterminate pulmonary infiltrations. It is hoped that this analysis will demonstrate the similar clinical pattern of the various fungus and granulomatous diseases of the lung, the variability of laboratory aids, the important role that surgery plays in both a positive and a negative sense, and the increasing need for finer and more accurate methods of diagnosis. By its very nature, this paper is also a further plea to clinicians to exhaust all available diagnostic methods, including surgery, before committing any given patient to a