Background context Patients with multiple myeloma (MM) are at increased risk of infections and suffer from poor bone quality due to their disseminated malignant bone disease. Therefore, postoperative complications may occur following surgical treatment of MM lesions. Purpose In this study, we aimed to determine the incidence of postoperative complications and retreatments after spinal surgery in MM patients. Additionally, we sought to identify risk factors associated with complications and retreatments. Study design Retrospective cohort study. Patient sample. In total, 270 patients with MM who received surgical treatment for spinal involvement between 2008 and 2021 were included. Outcome measures. The incidence of perioperative complications within 6 weeks and reoperations within 2.5 years and individual odds ratios for factors associated with these complications and reoperations. Methods Data were collected through manual chart review. Hosmer and Lemeshow’s purposeful regression method was used to identify risk factors for complications and reoperations. Results The median age of our cohort was 65 years (SD = 10.8), and 58% were male ( n  = 57). Intraoperative complications were present in 24 patients (8.9%). The overall 6-week complication rate after surgery was 35% ( n  = 95). The following variables were independently associated with 6-week complications: higher Genant grading of a present vertebral fracture (OR 1.41; 95% CI 1.04–1.95; p  = .031), receiving intramuscular or intravenous steroids within a week prior to surgery (OR 3.97; 95% CI 1.79–9.06; p  = .001), decompression surgery without fusion (OR 6.53; 95% CI 1.30–36.86; p  = .026), higher creatinine levels (OR 2.18; 95% CI 1.19–5.60; p  = .014), and lower calcium levels (OR 0.58; 95% CI 0.37–0.88; p  = .013). A secondary surgery was indicated for 53 patients (20%), of which 13 (4.8%) took place within two weeks after the initial surgery. We additionally discovered factors associated with retreatments, which are elucidated within the manuscript. Conclusion The goal of surgical treatment for MM bone disease is to enhance patient quality of life and reduce symptom burden. However, postoperative complication rates remain relatively high after spine surgery in patients with MM, likely attributable to both inherent characteristics of the disease and patient comorbidities. The risk for complications and secondary surgeries should be explored and a multidisciplinary approach is crucial.