Abstract. In this communication, we will present a very rare case of the coexistence of non-Hodgkin's lymphoma (NHL; low malignant lymphocytic lymphoma of the B-cell type) and a non-small-cell lung carcinoma (NSCLC). A patient with a 15-year history of NHL developed a generalized relapse of the lymphoma with an additional tumor mass in the left lower lobe of the lung. Bronchoscopy showed the evidence of the NHL. Due to non-responding chemotherapy on the lung tumor, the coexistence of a second malignancy was histologically proved in a second bronchoscopy. Resection of the lung tumor with complex lobectomy and lymphadenectomy was performed. After that, chemotherapy with four cycles of carboplatin supplemented with taxol was induced. The patient was discharged from the hospital with a stable remission of both tumor diseases. Restaging after six months showed no evidence of a tumor relapse. This is a very rare case of the coexistence of NHL and NSCLC; we will discuss the difficulty of diagnostic and treatment of both tumor diseases.