In tetraplegia patients, activities of daily living are highly dependent on the remaining upper limb functions. In other countries, upper limb reconstruction surgery to improve function has been applied to diverse cases, but few cases have been reported in Korea. The current authors experienced a case of posterior deltoid-to-triceps tendon transfer and rehabilitation in a complete spinal cord injury with a C6 neurologic level, and we introduce the case—a 36-year-old man—with a literature review. The patient's muscle strength in C5 C6 muscles were normal, but C7 muscles were trace, and the Spinal Cord Independence Measure III (SCIM III) score was 24. The tendon of the posterior deltoid was transferred to the triceps brachii muscle, and then the patient received comprehensive rehabilitative treatment. His C7 muscle strength in the right upper extremity was enhanced from trace to fair, and his SCIM III score improved to 29.