Despite the significance given to code-switching as a common linguistic phenomenon among bilinguals around the world, the reasons for which teachers in Turkish Persian classes–which are supposed to be run in Persian–resort to code-switching have not been intimately explored. In the first section of the present study, the data were collected from a primary school by tape recording and note taking from interactions taking place between bilingual teachers (n = 4) and their students. It was found that bilingual teachers in this study tended to use students L1 to serve a number of pedagogic and social functions. For the second section of the study, however, a questionnaire was developed to elicit bilingual teachers 
(n = 305) reasons for resorting to code-switching in elementary classes. The Friedman test run on the data collected from the questionnaire indicated that the majority of respondents agreed with code-switching in elementary schools, but they appeared to credit different reasons for such a change from Persian to Turkish in their classes. Code-switching mostly occurrs in the classroom to cater for the needs of the students. Code-switching functions justify its use in the class, but it shoud be used in some restricted activities.