This study aims to find out the usage of code mixing in the novel Bidadari Bermata Bening by Habiburrahman El Shirazy. It also aims to find out the types of code mixing. This study is supported by Bhatia and Richie’ theory(2006:337) about code mixing. It is stated that code mixing refers to the mixing of various linguistic units (morphemes, words, modifiers, phrases, clauses and sentences) primarily from two participating grammatical system within a sentence Besides that, this study is also based Suwito’s theory (1983, 76). He classified code mixing into two, they are: inner code mixing and outer code mixing. This study is conducted by using a qualitative descriptive method in analyzing finding and classifying mixed and mixed codes. In this analysis, the data used are the sentences and paragraphs which show the usage of code mixing in it. The result of the study shows that the form of insertion and also the types of code mixing that appear in the novel. There are two types of code mixing found in the novel. First, Inner code mixing (Indonesian and Javanese), its occurences in the form of word, phrase, repetition and clause insertion. Second, Outer code mixing (Indonesian and Arabic), its occurences in the form of word, phrase, and clause insertion.
Keywords: Code Mixing, Inner Code Mixing, Outer Code Mixing, Word Insertion, Phrase Insertion, Repetition Insertion, Clause Insertion