Background: Primary deltoid tendon rupture is a rare injury with limited reporting in the literature. This injury is most commonly seen in elderly patients with pre-existing rotator cuff pathology and usually occurs in an atraumatic, attritional fashion. Treatment options are limited and include symptomatic care, primary repair, and arthroplasty-based techniques involving a single stage reverse total shoulder arthroplasty with concomitant restoration of deltoid function through repair or muscle transfer. Primary repair is a good surgical option for restoration of function in low-demand patients with minimal surgical morbidity. Purpose: This video overview and case presentation demonstrates primary deltoid tendon repair involving the use of bone tunnels. Methods: The anatomy, pathogenesis, diagnosis, and treatment options for deltoid ruptures are reviewed. A case of a 73-year-old woman with a history of chronic massive rotator cuff tear and new ipsilateral deltoid rupture is presented. This injury occurred atraumatically and prevented the patient from performing her activities of daily living. After a thorough discussion of risks, benefits, and prognosis, the patient elected to proceed with primary deltoid repair to improve her functional status. Results: The deltoid origin was anatomically restored intraoperatively. Postoperatively, the repair was maintained both clinically and radiographically, although the patient had some personal setbacks that slowed her recovery. Conclusion: Primary repair is a viable surgical option for elderly patients with attritional deltoid ruptures in the setting of chronic rotator cuff tears. This treatment is simpler to perform than are single-stage arthroplasty-based techniques and can offer good functional results with less surgical morbidity. Adherence to postoperative rehabilitation is crucial for optimal outcomes.