To evaluate effects of a natural CPOE implementation in a hospital setting and inform the efficacy of using CPOE rather than traditional paper medication orders.A multiple-baseline, quasi-experimental study of a naturally occurring CPOE intervention, with a non-equivalent control site.Compliance with medication-ordering protocols and time to first dose of antibiotics.Medication orders placed using CPOE were significantly more compliant than paper-based medication orders, and first doses of antibiotics were delivered significantly faster when ordered with CPOE than when placed using the standard paper-based system (p<.01).Findings support the use of CPOE and justify the need for interventions to increase CPOE adoption and consistent use among physicians.