Postmortem radiographic examinations of animals are often performed in judicial investigation to rule out gunshot and fractures due to cruelty. Literature describing postmortem changes seen on radiographs of animals is rarely available. Serial thoracic radiography of six recently euthanized dogs was performed in an interval of 8 h at a tropical ambient temperature of 22-33 degrees C. Severe decomposition of the cadavers prevented the study to be performed beyond 24 h. Gradual increment of gas accumulation in the pleural cavity, mediastinum, esophagus, blood vessels, cardiac chambers and subcutaneous tissue was observed. Lung changes observed were typical of alveolar pattern and subsequently collapsed secondary to severe pneumothorax. Vacuum phenomenon of the scapulohumeral joints which was not documented in humans was seen in four cadavers. Most radiographic changes were detected at 16 h post-euthanasia. Severe subcutaneous emphysema developed between 16 and 24 h post-euthanasia. This study showed that rapid postmortem changes which could be detected radiographically occur within 24 h of death at the ambient temperature of 22-33 degrees C.