Using the sequential analysis developed by Auer(1984, 1995), this paper presents an analysis of bilingual learner code-switching between first language (L1: English) and second language (L2: Korean) in an intermediate Korean as a foreign language(KFL) classroom. The procedures of Conversational Analysis(CA) are adopted, with particular attention to the way in which code-switching contextualizes particular conversational procedures. Evidence is presented to suggest that participants deploy code-switching as a resource to help them contextualize preference organization(Pomerantz, 1984). Specifically, dispreferred responses such as disagreement, negative evaluation may (but not necessarily always) be handled through the use of contrastive language choice. Code-switching to L1 (i.e. English) is used as one among several strategies in order to maintain of dispreferred responses. Contrary to the assumption that code-switching is evidence of linguistic deficit in bilingual speakers, the sequential analysis suggests that code-switching is used as an additional resource to achieve particular conversational goals in interactions with other bilingual speakers.