Infections caused by Cunninghamella bertholletiae are being identified with increasing frequency in immunocompromised patients. We have treated two children with cancer for pulmonary infections caused by this rare fungus. Cunninghamella infection is found in a variety of populations of patients, including both children and adults undergoing chemotherapy. Clinical signs and symptoms are indistinguishable from those of other forms of zygomycosis. Outcome is poor: only three of 17 patients with such infection (including one of the two children described herein) have survived. Treatment involves aggressive surgical excision and administration of amphotericin B.