OBJECTIVES: Presently, no published studies compare head-to-head long-acting injectable (LAI) antipsychotics paliperidone palmitate (PP) and olanzapine pamoate (OLANZ) for  schizophrenia; therefore, this indirect analysis was undertaken to examine long-term relapse rates. METHODS: A priori criteria included: Patients: adults ≥18 with DSM diagnosis of schizophrenia, non-suicidal outpatients with stable disease, taking minimal other medications; Designs: placebo-controlled, double-blind, stabilized on LAIs and treated long-term; Outcome was relapse rate; Definitions: must have defined relapse and stabilization. We compared between LAI and placebo within studies using risk ratios (RR) for relapse rates derived from Kaplan-Meier curves. Bucher’s method was used to compare indirectly between LAIs. RESULTS: We identified two similar trials, one for each LAI. At randomization, patients had similar mean±SD age (PP=39.1±11.1, OLANZ=38.9±11.2), BMI (PP=27.3±5.8, OLANZ=26.9±5.0), and PANSS-Total scores (PP=52.6±11.8, OLANZ=55.8±15.2). Research designs and definitions were also comparable. For a valid comparison, outcomes at 24 weeks were analyzed. In the PP trial (Hough; Trial PSY-3001), 206 patients received PP (50 or 100 mg Eq, which could be adjusted to 25, 50 or 100 mg Eq; average dose: 82.8 mg/4 weeks; 1.18 daily-defined-doses[DDDs]), 204 received placebo. In the OLANZ trial (Kane; Trial HGKA), 599 patients were randomized to receive OLANZ (150 mg/2 weeks, 405 mg/4 weeks, or 300 mg/2 weeks; average dose: 426 mg/4 weeks; 1.52 DDDs) and 144 received pseudo-placebo (45 mg/month), a very low clinically sub-therapeutic dose assumed to be comparable to placebo. PP had significantly fewer relapses than placebo (RR=0.31; CI95%:0.22-0.44) as did OLANZ (RR=0.33, CI95%:0.24-0.46). The indirect RR of OLANZ versus PP was 1.06 (CI95%:0.65-1.72). However, the monthly dose was 29% higher for OLANZ (426 mg, 1.52 DDDs) than for PP (82.8 mg, 1.18 DDDs).  CONCLUSIONS: No differences were found in 6-month relapse rates between LAIs; however, OLANZ required higher DDDs. These findings could impact outcomes from cost-effectiveness analyses.