Background: Meropenem, a broad-spectrum carbapenem with potent in vitro activity, is postulated to be an effective monotherapy for the treatment of complicated skin and skin structure infections (cSSSI). Methods: This multicenter, international, double-blind, randomized, prospective study of hospitalized patients with cSSSI evaluated the efficacy, safety, and tolerability of meropenem (500 mg IV q8h) versus imipenem-cilastatin (500 mg IV q8h). The primary efficacy endpoint was clinical outcome at follow-up in the clinically evaluable (CE) and modified intent-to-treat populations (MITT; patients who met eligibility criteria and received at least one dose of study drug). The study aimed to demonstrate non-inferiority (delta of 10%, 95% confidence intervals) in clinical response in the CE population. Clinical responses for all pathogens at follow-up were assessed in the fully evaluable population (CE population with baseline pathogen and follow-up cultures). Results: In total, 1,076 patients were enrolled. Of these, 692 patients comprised the MITT population (334 and 358 patients randomized to meropenem and imipenem-cilastatin, respectively) and 548 the CE population (261 and 287 patients randomized to meropenem and imipenem-cilastatin, respectively). Cure rates were 86.2% (meropenem) and 82.9% (imipenemcilastatin; 95% CI, -2.8, 9.3) in the CE population and 73.1% (meropenem) and 74.9% (imipenem-cilastatin; 95% CI, -8.4, 4.7) in the MITT population. The frequencies of adverse events and drug-related adverse events were similar between treatment groups. Conclusion: In one of the largest studies conducted to date of hospitalized patients with cSSSI, meropenem, 500 mg IV q8h had comparable safety and efficacy to imipenem-cilastatin, 500 mg IV q8h.