Unplanned readmissions after spine surgery are undesired, and cause significant functional, and financial distress to the patients and healthcare system. Though critical, knowledge about readmissions after surgery for traumatic spinal injuries (TSI) is scarce and under-evaluated. Consecutive patients surgically treated for TSI and who had unplanned readmission within 90 days post-discharge were studied. Peri-operative demographic and surgical variables, surgical treatment, level of injury, delay in surgery, ASIA score, other organ injuries, peri-operative complications, smoking, ICU stay, co-morbidity, and the length of hospital stay were studied and correlated with the causes for readmission. Among 884 patients, 4.98% (n = 44) had unplanned readmissions within 90 days of discharge. Notably, 50% (n = 22) patients were readmitted within the first 30 days. The common causes of readmissions were urinary tract related problems (27%, n = 12), pressure ulcers (20.4%, n = 9), respiratory problems (13.6%, n = 6), surgical wound related problems (14%, n = 7,) limb injuries (11.4%, n = 5), and others (11%, n = 5). The total beds lost secondary to readmissions was 314 days, and the mean bed-days lost per patient was 7.2 ± 5.1. Thirteen peri-operative risk factors were associated with unplanned readmissions, among which, smoking (OR 2.2), diabetes (OR 2.4), and pressure sore during index admission (OR 16.7) were strong independent predictors. The incidence of unplanned readmissions after TSI was 5%, which was similar to elective spine surgeries but the causes and risk factors are different. Non-surgical complications related to urinary tract, respiratory care and pressure sores were the most common causes. Pre-operative smoking status, diabetes mellitus and pressure sores noted in the index admission were important independent risk factors.