This study examines the manifestations of purity and authenticity in 47 Basque bilinguals' reactions to code-switching. The respondents listened to two speech extracts with code-switching, filled in a short questionnaire and talked about the extracts in small groups. These conversations were then recorded. The respondents' beliefs can be characterized as considerably ambiguous. They see code-switching as an undesirable form of speech and as a threat to Basque. However, they admit using it in informal contexts. Although the respondents prefer the "pure" form of Basque without code-switching, and some of them favor translation as an alternative strategy, purity is not considered authentic or even possible in situations such as peer-group interactions. Furthermore, code-switching is interpreted differently according to the linguistic background of the speaker: if the speaker is considered a native speaker of Basque, code-switching is seen as natural, whereas in the speech of a non-native speaker it is considered to reflect a lack of competence in Basque.