This study investigates public attitudes towards medicinal waste and medicines reuse within a ‘free prescription’ healthcare system. A quantitative online survey was employed in a sample drawn from the population of Wales, where prescription medicines have been ‘free’ since 2007. Qualitative interviews informed the content of the attitude statements with categorical or ordinal response options assigned. The questionnaire was hosted on the HealthWise Wales platform for 1 year from October 2017. Of the 5584 respondents, 67.2% had at least one medicine on repeat prescription. Overall, 89.1% held strong concerns about medicinal waste. High acceptance for the reuse of prescription medicines which have been returned unused by patients to pharmacies was reported for tablets (78.7%) and capsules (75.1%) if the medicine is checked by a pharmacist first (92.4% rated essential). Concerns identified related to tampering of packs (69.2%) and the need for hygienic storage (65.4%). However, those working in healthcare had less concern about the safety of reusing medicines. The level of public acceptance for the reuse of medication was higher than previously reported. This is the largest survey to capture these views to date, which has implications for the future design of medicines reuse schemes.