Background Pulmonary complications are important cause of morbidity and mortality in patients following spinal surgeries. There is paucity of literature on pulmonary complications following complex spine deformity surgery in underserved regions. This study sought to assess the incidence and risk factors of pulmonary complication following complex spine deformity surgery Methods Data of 276 complex spine deformity patients aged 3-25yrs who were consecutively treated at a single site were retrospectively reviewed. Data was analyzed using Stata 14 software. Patients were labelled into two groups: Grp 1: patients with pulmonary complications(N=17) vs Grp 2: patients with no pulmonary complications (N=259). Comparative analysis for risk factors included independent t-test and chi square test for independence. Multivariate logistic regression analysis was also performed. Results The incidence proportion of pulmonary complication was 17/276 (6.1%) (Grp 1) whiles 259 pts had no pulmonary events (Grp 2). There were 8M/9F for Grp 1 vs 100M/159F Grp 2, p=0.48. BMI was similar in both groups (17.2 vs 18.4km -2 , p=0.15). Average pre-op sagittal cobb (90.6 vs 88.7deg, p=0.87.), coronal cobb (95 vs 88.5deg, p=0.43), Pre-Op FVC (45.3 vs 62.0%, p=0.02), Pre-Op FEV1 (41.9% vs 63.1, p<0.001), Grp 1 vs Grp 2, respectively. EBL, OR time and Surgery Levels were similar in both Grps. Thoracoplasty was performed in 41.18% vs 21.57%, p=0.06, SPO 47.06% vs 42.31%, p=0.04 and VCR 5.88% vs 20.31%, p=0.145, Grp 1 vs Grp 2, respectively. Multivariate logistic regression showed that every unit increase in pre-Op FVC (%) decreases the odds of pulmonary complication by 5% (OR=0.95, 95% CI 0.90 to 0.99, p=0.045). Conclusion The observed 6.1% incidence of pulmonary complications is comparable to reported series. Only pre-Op FVC was an independent predictor of pulmonary complications. The observed case fatality rate (17%) following pulmonary complications highlights the need for thorough preoperative evaluation to identify high risk patients. Key words: Complex spine deformity; Pulmonary complications; late presentation; Forced Vital Capacity; Halo Gravity Traction; FVC; pediatric deformity; scoliosis; Pulmonary function tests; PFT; complications; Preoperative management.