OBJECTIVE To investigate the pulmonary dysfunction patterns in patients of scoliosis associated with neurofibromatosis type I (NF1) and to identify factors affecting the pulmonary function in patients with scoliosis associated with NF1. METHODS Preoperative pulmonary function tests (PFTs) were evaluated in 100 patients with scoliosis [NF1 group, 36 cases; idiopathic scoliosis (IS) group, 64 cases] from January 2003 to June 2009. According to location of apical vertebra and dystrophic change in patients with NF1, the parameters of pulmonary function [vital capacity (VC), forced vital capacity (FVC), forced expiratory volume in one second (FEV1), maximal mid-expiratory flow (MMEF), maximal voluntary ventilation (MVV)] were compared between NF1 group and IS group, and between the subgroups of NF1. The correlation between pulmonary function parameters and radiographic parameters of scoliosis was analyzed. RESULTS The VC, FVC, FEV1, MMEF, MVV in NF1 group and IS group were of no significant difference (P > 0.05). In NF1 patients, the pulmonary dysfunction was more severe in thoracic subgroup than non-thoracic subgroup (P < 0.05), while there was no difference between dystrophic scoliosis and non-dystrophic scoliosis (P > 0.05). The location of apical vertebra and the severity of scoliosis correlated significantly with the pulmonary dysfunction in NF1 group. CONCLUSIONS The pattern of pulmonary dysfunction in scoliosis associated with NF1 is similar with IS. Pulmonary dysfunction is more severe in thoracic scoliosis. The location of apical vertebra and the severity of scoliosis are the risk factors influencing the pulmonary dysfunction.