Background: The purpose of this study is to compare the incidence of complications associated with tension band wiring (TBW) versus plate osteosynthesis (POS) in the treatment of olecranon fractures. Methods: We performed a retrospective cohort study of operatively treated adult olecranon fractures from an integrated healthcare system by multiple surgeons from January 2008 to December 2011. Patients were divided into two cohorts: fractures fixed using the tension band technique and fractures fixed using plate osteosynthesis. The study was limited to the Orthopedic Trauma Association classification of olecranon fracture type 21-B1, with subtypes 1-3. Outcome measures were loss of fracture fixation requiring revision, postoperative infection, stiffness requiring surgery, and symptomatic hardware removal (HWR). Univariate and multivariable logistic regressions were performed to test the associations between the type of internal fixation and outcomes. Results: A total of 321 olecranon fractures were included (median age: 61 years old, 57 % female),153 participants were treated with TBW, and 168 patients with POS. There was one failure in the TBW group and two in the POS group (P=0. 62). There were no significant differences in the infection rates (TBW 5%, POS 9%, P=0. 20) and no reoperations for stiffness. The HWR occurred significantly more often in TBW (29%) than in POS (14%) (OR=0. 39, P=0. 001). The association between POS and decreased HWR remained highly significant (OR=0. 40, P=0. 003) after adjusting for clinical variables. Conclusion: In this large study comparing POS and TBW for 21-B1 olecranon fractures, no difference in fixation failure, infection, or postoperative stiffness was noted. A significantly greater risk of symptomatic hardware occurred in TBW. These findings may assist surgeons and patients in considering the risks and benefits of TBW and POS as treatment options for displaced olecranon fractures.