The object of this study was to evaluate the durations from onset of neurological sign until surgery and regaining of the deep pain perception (DPP) after decompression as prognostic indicators for the outcome of decompression surgery in dogs with thoracolumbar intervertebral disc disease (IVDD). The compression lesions in the thoracolumbar vertebrae were localized by plain radiograph, computed tomography and neurological examination in 28 dogs with hindlimb paralysis. The follow up was carried out for 6 months after laminectomy. During the follow up, regaining DPP and walking ability were evaluated. Improvement to normal or paretic gait after surgery was judged as success of the surgical treatment.The success rate of surgical treatment was 70 % (7 out of 10 dogs) when surgical intervention was carried out within 24 hours but 38.9 % (7 out of 18) over 24 hours (P<0.05). The success rate of surgical treatment was 87.5 % (14 out of 16 dogs) when DDP was regained within 5 weeks after surgery but there was 0 % (0 out of 12 dogs) when DDP was not regained within 5 weeks after surgery (P<0.05). Other parameters such as compression rate in CT scan and laminectomy methods did not related with the success of the surgery. These results suggested that the time of surgery after onset and duration of regaining of DPP after decompression were useful parameter to predict the success of surgical treatment for thoracolumbar disc herniation in dogs.