This study aims to investigate the effects of a vocalization-based respiratory training intervention on forced vital capacity (FVC) and peak expiratory flow rate (PEFR) in patients with a cervical spinal cord injury in a recovery phase, ultimately to present clinical evidence for an efficient respiratory physical therapy. Fifteen participants with a cervical spinal cord injury were randomized to the vocalization-based respiratory training group (n=8) and incentive spirometry training group (n=7). The participants underwent 30 minutes of conservative physical therapy and additionally underwent 15 minutes of their corresponding intervention (respiratory training and incentive spirometry) five times a week for four weeks. Prior to the intervention, pulmonary function tests were performed to analyze FVC and PEFR, both of which were measured again after four weeks of intervention. The values were compared within and between groups. Both groups showed significantly increased FVC and PEFR after the intervention, and the FVC and PEFR in a seated posture significantly differed between the vocalization-based respiratory training group and the incentive spirometry group (p<.01). In the supine position, FVC did not significantly differ between the two groups (p>.05). The results of this study show that vocalization-based respiratory training is more effective in improving FVC in a seated posture and PEFR in the supine position. Vocalization-based respiratory training would improve pulmonary function parameters in patients with cervical spinal cord injury, and additional studies are needed based on these results to examine a variety of variables according to the type of respiratory training technique.