The course of the bronchial carcinoma and the therapeutic chances are influenced by the histologic tumor type which determines the respective biologic behavior. The most important clinical finding is the differentiation between small-cell and non-small-cell bronchial carcinomas. Small-cell bronchial carcinomas are characterized by a rapid duplication of the tumor volume, a high rate of cell divisions and an early hematogenic and lymphogenic dissemination. They have therefore a good response to antiproliferative chemotherapy. In almost 80% of patients bronchial carcinomas with limited disease, a complete remission and a markedly prolonged median survival time can be achieved by combined cytostatic chemotherapy, e.g. the therapy regimens ACO I and ACO II. As yet, the problem of local and remote recurrences is not solved. The unfavorable prognosis of the primarily inoperable small-cell bronchial carcinoma can be improved by chemotherapy. On the other hand, the high remission rate is diminished by later incurable recurrences. A pretherapeutic differentiation of limited and extended disease is necessary. The necessity and conditions of an additional radiotherapy have to be determined later on by means of prospectively randomized therapy studies. As opposed to the small-cell bronchial carcinoma, the non-small-cell bronchial carcinoma shows a markedly lower response to chemotherapy. Adenocarcinomas are comparatively refractory to chemotherapy, but squamous cell carcinomas respond now a little better to chemotherapy.