Providers underutilize evidence-based practice guidelines as they prescribe contraceptives. To discern biases in guideline utilization by 172 providers of three countries, this study used observations from simulated clients trained to choose oral contraceptives. Providers implemented less than one third of the guideline set, but they addressed, more frequently than other guidelines, items categorized as essential by expert opinion (p < .01). Indian providers emphasized instructions on method use in 9-minute consultations, Rwandan providers emphasized contraindications in 29-minute sessions, and Peruvian providers did not emphasize any single guideline category. Providers should use job aids to improve guideline utilization. Those pressed for time need an evidence-based, rather than arbitrary, selection of essential guidelines that optimizes client outcomes. Practice-based research must be generated to meet this need.