The dynamics of morphological changes occurring in the bronchial stump depending on the extent of mediastinal lymph dissection, preoperative chemotherapy and the stump cover method are discussed. Stump healing after right-side pneumonectomy was assessed in 32 non-inbred dogs. Typical procedure was tested in group 1 while complete systematic mediastinal lymph dissection (CSMLD)--in groups 2-4. In groups 3-4, pneumonectomy was performed after two courses of chemotherapy (cisplatin 80 mg/m2 per day + etoposide 120 mg/m2, days 1,3,5). In groups 1-3, the stump was covered with a parietal strap; in group 4, a m. latissimus dorsi strap was fixed on a vascular "pedicle". Experiment was suspended on days 3, 7, 14, 21 and 30. One animal in group 2 died of ischemic necrosis of the esophagus terminating in mediastinitis. None of the animals developed bronchial fistula. Angiography detected reduced blood flow in the right-side third of the trachea and medial surface of the left main bronchus in the CSMLD groups. Microscopically, all the groups revealed a similar pattern of stump healing. CSMLD did not influence bronchial stump regeneration significantly. Nor was it hampered in any way by preoperative chemotherapy. The latter was followed by expansion of necrotic and edematous area thus slightly affecting regeneration. Primary bronchoplasty failed to speed up regeneration, yet it might diminish the risk of bronchial fistula.