Objective: The purpose of this study is to evaluate the effectiveness of a family-centered early exercise program in infants with Narakas Stage 1 brachial plexus birth palsy. Method: The data of the infants with brachial plexus birth palsy followed up at the physical medicine and rehabilitation outpatient clinic of a tertiary pediatric research center were retrospectively investigated. Infants with Narakas Stage 1 brachial plexus birth palsy according to the Narakas classification were included in the study. Sixty infants were assessed using a passive-active range of motion (ROM) and active movement scale at first clinic visit and every month until they became 12 months old. Results: Cases were divided into two groups (Group I, n: 32) or (Group II, n: 28) according to their referral times to the outpatient clinics of physical medicine and rehabilitation. In both groups, a significant improvement was observed in the ROM and muscle strength of shoulder, elbow flexion, and forearm supination at the 3rd, 6th and 12th-month assessments. At 12th months intergroup differences were detected in shoulder abduction muscle force assessments (p<0.05) and active ROM measures of shoulder abduction-internal rotation-external rotation and forearm supination (p<0.05). Conclusion: Family-centered early therapy program is effective against complications that may occur in the first year of infants with Narakas Stage1 brachial plexus birth palsy. In infants with brachial plexus birth palsy, not only neurological improvement should be focused, but also regular follow-ups should be made regarding complications.