Does codeswitching between Spanish and English signal an inherently less formal register? A range of material examined supports this hypothesis. Codeswitching is seen less in prose, and within that framework surfaces very little in scholarly writing. It is used most often in dialogue, many times in forms meant to be representative of linguistic variation or stream-of-consciousness style utterances. In this paper the relationship between register and the presence or absence of codeswitching in both fiction and nonfiction writing is examined. In addition to literary and critical sources, data come from a survey of the writing habits and attitudes of individuals who use codeswitching in their speech. Some comparison is made to other language pairs.