Abstract With the evolution of written language in China language and the sociolinguistic situation in Hong Kong as the background, this thesis investigates patterns and functions of code-switching with Standard Written Chinese, Written Cantonese and English in Hong Kong magazines. It is suggested the major locus of variation in patterns and motivations of code-switching lies with the different types of magazines whose style, contents and background vary from one another. The magazines are classified into five types, namely, News and Comprehensive, Business and Finance, Life and Travel, Fashion (Women and Men), and Entertainment and Celebrities, and two issues from two magazines of each category were collected for data analysis. The major motivations of code-switching (to English) attested in all five categories are authenticity, medium repair, audience design and topic, but the related patterns are of different frequencies in various types of magazines.