This study analyses the phenomenon of code switching by clothes sellers in Pasar Atjeh. This descriptive qualitative research was conducted to find out the types and factors which cause the occurrence of code switching. It focused on the using of Acehnese-Indonesian switching among the clothes sellers. The data were collected by observation and interview. The writer applied the theoretical framework based upon Wardhaugh (2010) and Poplack (1980) to classify the types of switching, and Holmes (2017) and Suwito (1985) to identify the factors which triggered the occurrence of code switching. The data were analyze by using step procedures namely data reduction, data display and conclusion as suggested by Miles and Huberman (1994). The result show there are five types of code switching were identified as follows 1) situational switching; 2) metaphorical switching; 3) tag-switching; 4) inter-sentential switching and 5); intra-sentential switching. The finding also indicates code switching was triggered by some factors there were the speakers, participant of speaking, the arrival of third participant, topic of conversation, and sense of humor.