Miconazole was administered intravenously in six consecutive patients with, active coccidioidal infection. Such treatment was associated with progressive anemia and thrombocytosis. The hematological abnormalities appeared to be dose related and potentially reversible. Bone marrow studies demonstrated erythroid hypoplasia and increased or active platelet production in three subjects. No hemorrhagic or thrombotic episodes were identified. It is suggested that careful hematological monitoring be performed in subjects undergoing systemic miconazole therapy.