A review was made of the presentation, treatment, and follow-up of 20 patients with adenoid cystic carcinoma and 12 patients with mucoepidermoid carcinoma of the bronchus who were seen at the Mayo Clinic during the 50 year period 1927 through 1977. Three forms of therapy were employed: complete surgical resection, radiation therapy alone, and radiation therapy after endoscopic removal of tumor tissue. Superior results were obtained in the group with adenoid cystic carcinoma, when complete resection was possible. Significant survival and palliation of sepsis was achieved with subtotal resection. The mucoepidermoid carcinomas in this series were classified on the basis of histologic differentiation. Mucoepidermoid carcinoma of Grade 1 was managed by conservative pulmonary resection. Mucoepidermoid carcinoma of Grades 2 and 3 showed a greater propensity for malignancy. Widespread dissemination caused death with unresectable high-grade mucoepidermoid carcinomas of Grades 2 and 3.