Following a large regulatory reform in 2009, which ended the state's pharmacy monopoly, non-pharmacy retailers in Sweden today sell certain over-the-counter (OTC) drugs. The aim of this study was to investigate consumer preferences regarding OTC drug retailers and the reasons for choosing a pharmacy versus non-pharmacy retailer. We conducted a web survey aimed at Swedish adults. Out of a stratified sample of 4058 persons, 2594 agreed to take part (48% women; mean age: 50.3 years). Questions related to OTC drug use, retailer choice and factors affecting the participants' preferences for OTC drug retailers. Logistic regression was conducted to analyse OTC drug use and reasons for retailer choice in relation to sex, age and education. Nine in ten participants reported OTC drug use in the 6 months prior to the study. For their last OTC purchase, 76% had gone to a pharmacy, 20% to a grocery shop and 4% to a convenience store, gas station or online. Geographic proximity, opening hours and product range were reported as the most important factors in retailer choice. Counselling by trained staff was important to 57% of participants. The end of the state's pharmacy monopoly and the increase in number of pharmacies seem to have impacted more on Swedish consumers' purchase behaviours compared with the deregulation of OTC drug sales.