To date, few studies have investigated the clinical characteristics of thoracolumbar intervertebral disc protrusion (IVDP). The aim of this retrospective study was to evaluate the presentation and outcome of dogs receiving medical or surgical treatment for thoracolumbar IVDP. Eighty-four dogs were included, with a median age of 9.4 years. German shepherd dogs and Staffordshire bull terriers were the most common breeds. Significantly more surgically treated dogs (n=53) had neurological deficits and were non-ambulatory, compared with medically treated (n=31). Outcome data were available for 27 of 31 medically managed dogs; 11 initially improved, 7 remained stable and 9 deteriorated. Of 18 dogs that initially improved or stabilised, 10 (55.6 per cent) demonstrated recurrence of clinical signs within 12 months of diagnosis. Outcome data were available for 45 of 50 surgically treated dogs that survived to hospital discharge; 34 improved, 9 remained stable and 2 deteriorated following surgery. Of 43 dogs that improved or stabilised with surgical treatment, 11 (25.6 per cent) demonstrated recurrence of clinical signs within 12 months of surgery. Overall, significantly more surgically treated dogs (71.1 per cent) had a successful outcome, consisting of sustained clinical improvement of more than 12 months duration, compared with medically treated dogs (29.6 per cent).