BACKGROUND: Little is known about physician ability to utilize Boolean search skills to access information. PURPOSE: Determine the proficiency of medical students and practicing physicians to identify efficient Boolean phrases. METHODS: Experiential survey and multiple-choice questions administered to 49 4th-year medical students and 42 practicing physicians. Subjects identified the best answer or correctly ranked 3 Boolean search phrase options. RESULTS: Practicing physicians identified the single best query phrase significantly more often than did medical students (85.7% vs. 75.0%, p < 0.001), and both groups had significantly more difficulty correctly rank-ordering the queries (students, 75% vs. 54%, p < 0.001; practitioners, 85.7% vs. 57.1%, p < .04). Only recent MEDLINE use was an independent predictor of accuracy in both groups. CONCLUSION: Students and physicians demonstrated deficiencies in identifying optimal Boolean phrases. Although formal instruction has not demonstrated clear improvement in skills, more creative teaching of Boolean search techniques should be undertaken and tested.