Abstract
Code-switching is the use of more than one language in one conversation.This phenomenon is not only happening in the bilingual or multilingual family but also in a society where two or more languages are used functionally.This case was found in students' postgraduate online class of the English department at FKIP, University of Mataram.This study aimed to identify types of codeswitching those postgraduate students used and how they used them.It employed a descriptive qualitative method and used observation, recording, and note-taking as instruments to collect the data.The findings show that there are three types of code-switching used by communicators: intra-sentential, inter-sentential, and tag code-switching which belong to Poplack theory.Students switch the languages between the English-Indonesian language and Indonesian-Sasak Language.And the type which is most widely used is intra-sentential code-switching.