PurposeThis study aimed to explore physicians use of drug information in professional work, with special focus on those working in primary care, and also in relation to personal characteristics of physicians.MethodsA web-based questionnaire was distributed by e-mail to physicians in five regions in Sweden. The questions concerned drug-related queries at issue when searching for information, sources used, and factors of importance for the choice of source, as well as responder characteristics.ResultsA total of 3254 (85%) out of 3814 responding physicians stated that they searched for drug information every week. For physicians working in primary health care, the corresponding number was 585 (96%). The most common drug-related issues searched for by 76% of physicians every week concerned pharmacotherapeutic aspects (e.g., dosing), followed by adverse drug reactions (63%). For 3349 (88%) physicians, credibility was the most important factor for the choice of sources of drug information, followed by easy access online (n = 3127, 82%). Further analyses among physicians in primary care showed that some personal characteristics, like seniority, sex, and country of education, as well as research experience, were associated with usage and preferences of drug information sources.ConclusionsThis study confirms that physicians often use drug information sources in professional work, in particular those who work in primary health care. Credibility and easy access are key factors for usage. Among physicians in primary care, personal factors influenced the choice of drug information sources.