Clavicle fractures represent 2.5-4% of all fractures observed in emergency services. 80% occurs in the middle third. Treatment by plating requires a higher level of evidence. To compare the functional outcomes of mid-shaft clavicle fractures managed with superior plating compared to anteroinferior plating. A randomized, double-blind, parallel, superiority clinical trial. Patients with fractures of the clavicles AO15B1 and AO15B2 were studied. Patients were randomized to be treated with either 3.5 mm superior or anteroinferior plating. A rehabilitation program was designed for both groups. The primary outcome measure was the Disability of Arm, Shoulder, and Hand (DASH) score; secondary outcomes included pain, union rate, and complication rates. Twenty-eight patients were studied and were eligible for analysis. Significant differences were found in the function assessed with the DASH score at 30 days for the superior plating compared with anteroinferior (43.74 vs. 29.26, respectively, p = 0.027), 60 days (23.97 vs. 11.18, p = 0.021), and 90 days (9.52 vs. 3.5, p = 0.016). One loosening with superficial infection was found with superior plating. Using an anteroinferior reconstruction plate in diaphyseal fractures offers better functional results than the upper plate in patients with fractures of the middle third of the clavicle.