Code-switching (CS) is a communicative strategy used by ESL bilingual teachers to teach English as a second language to non-native English speakers. Based on quantitative analysis of transcribed data from thirty ESL teachers at Pakistani universities, the present study examined the influence of code switching (CS) on ESL learners in Pakistan, exploring in particular the impact of CS on and teacher attitude towards CS in ESL instruction. The findings of the study indicate significant use of code-mixing and frequency of mixing words, phrase and the smallest unit of one language into another language. Furthermore, the findings suggest that CS is frequently used by the ESL teachers. The study also highlights that common nouns are followed by proper nouns, adjectives, verbs and abbreviations, with the most significant words used during instantiation of CS in the data comprising lexical items, phrases, compound words, and encouraging words. Thus, this study suggests that CS is used to facilitate the comprehension and participation of the bilingual learners.