A new proximal humerus nail (Sirus) for the treatment of proximal humerus fractures has become available. This paper presents the clinical and radiological outcome of the first collective study of 36 patients. Evaluation was performed prospectively. An antero-acromial approach was used for all patients. Three fixed-angle screws were inserted in a locking technique. Thirty-six fractures were fixed with the Sirus nail. These were dislocated 2- and 3-part fractures as described by Neer (J Bone Joint Surg 52:1077-1089). Outcomes were evaluated using the Constant score. Of the 36 patients evaluated 23 had sustained a 2-part fracture and 13 a 3-part fracture. The average age at surgery was 71.2 years (range, 30-93). In 75% of the cases, good to very good outcomes were achieved. Outcomes were satisfactory in 13.8% of the cases. Twenty-five fractures were treated in a closed technique. Average operating time was 41 minutes (range, 19-106) with a fluoroscopy time of 0.6 minutes (range, 0.4-2.6). Secondary fragment dislocation occurred in two cases. After 12.1 months the average Constant score was 79.2 (range, 46-100). Initial clinical experience with the Sirus nail indicates that the procedure is straightforward and has a low complication rate. Functional outcomes are predominantly good to very good. Large fragments of the greater tuberosity and 4-part fractures are beyond the scope of this application.