This paper attempts to investigate Chinese-English code-switching behaviour present in blogs (a kind of computer-mediated communication) belonging to young people in Macao. The first goal of this study is to describe the patterns of Chinese-English code-switched language in 200 blog entries written by 20 Macao young people and the second goal is to use language, computer and social contexts in order to analyze the possible motivations behind the code-switching behaviour of these bloggers. As a result of this study, it is discovered that although the Chinese-English code-switched language in blogs is largely an extension of language used in spoken interactions or written press, there are still some distinctive features which set it apart from the code-switched language used in other genres. In addition the study also reveals that linguistic motivations play a significant role in bringing about Chinese-English code-switching in personal blogs, while computer-related motivations for code-switching are also considered important by some bloggers.