The Peruvian Ministry of Health has distributed insecticide-treated nets (ITNs) in the country's Amazon region since 1999. Net use is nearly universal among mestizo communities in this area, but residents traditionally use non-impregnated muslin nets. We evaluated the cultural acceptability of Ministry ITNs using qualitative methods. Our results show that nets serve various functions for users: protection against insect bites, warmth, privacy, and a sense of security for young children. Because the Ministry-distributed ITNs could not fulfill these functions as well as traditional nets, many recipients disliked or rejected the ITNs they received. Also, because the ITN fabric stains rapidly, recipients washed their nets frequently rather than waiting 6 months as recommended. We propose a two-pronged approach that balances user and health system expectations of bed nets and that should lead to more widespread and effective ITN use in the study communities. Copyright © 2008 by The American Society of Tropical Medicine and Hygiene.