This study compared the perception, knowledge, and use of generic drugs by adults in Pelotas, Rio Grande do Sul State, Brazil, using two cross-sectional population-based studies from 2002 and 2012. Study outcomes were: (a) prevalence of use of generics; (b) generics as a proportion of all medication; (c) users' perceptions of prices and quality; (d) users' knowledge of generics; and (e) strategies for acquisition of medicines. Prevalence of generics use increased from 3.6% (95%CI: 3.0-4.3) to 26.1% (95%CI: 24.5-27.7) in the 10-year period. Perceptions of prices and quality of generics remained stable, identification of characteristics that distinguish generics from other drugs improved (p < 0.001), and drug classification errors decreased (p < 0.001). There was a significant increase in acquiring medication by replacing prescribed drugs with generics. Between 2002 and 2012 there was an increase in knowledge and use of generics, while perception of lower prices and equivalent quality remained high.