Purpose <p>Timing of emergent surgery for lumbar disc herniations, such as cauda equina syndrome, remains a challenging aspect of best medical practice in spine surgery, with most authors recommending decompressive surgery as soon as feasible. The literature conflicts on the merit and potential risk of emergent, “out-of-hours” decompression. Our aim was to evaluate if there is a higher complication rate associated with out-of-hours decompressive surgery for emergent lumbar disc herniations.</p> Methods <p>This was a single-centre, retrospective cohort study in a tertiary referral spinal unit of patients who underwent emergency decompressive surgery for acute disc herniation. Demographic and clinical data, surgery type and level, timing, primary operator, intra-operative complications and revision surgery at 6 weeks and 1 year were recorded. Out-of-hours operating was defined as occurring between 20:00 and 08:00. Multivariable analysis was performed by multiple logistic regression. Statistical analysis was performed with R, version 4.4.1.</p> Results <p>There were 344 sequential, emergency decompressions for acute disc herniation performed during the study period. The mean age was 46 years (SD: 14) and 53% were female. Of cases, 129 (38%) were performed out-of-hours, compared to 146 (42%) during normal working hours and 69 (20%) during daylight weekend hours. There were 35 (10%) intra-operative complications; while 29 (8%) patients required re-operation within 6 weeks. On multiple logistic regression, out-of-hours surgery was not associated with either frequency of intra-operative complications or re-operations at 6 weeks. There were no independent predictors of intra-operative complication or revision surgery at 6 weeks or 1 year among age, sex, indication for surgery or grade of primary operator.</p> Conclusion <p>In this study, out-of-hours emergency decompression for acute lumbar disc herniation is not associated with intra-operative complication or revision surgery at one year.</p>