A Comparative Conversation Analysis Study of English for Schools series and American English File series based on Hutchby and Woffitt (1999) model Regarding Adjacency Pairs and Openings and Closings As Roth and Aberson (2008) point out, there are certain rules and frameworks in every language within which the speakers of that particular language communicate with each other. The different ways for asking for a favor, showing agreement and of course disagreement in a polite manner, using proper vocabulary in different situations, having a clear manner in sharing experiences etc. are among the main requirements to an effective interaction. The present study seeks to analyze and compare the conversations provided in English for Schools series and American English File series in order to find out the similarities and differences between the books which are written by native speaker authors and Iranian authors. In order to achieve this goal, 196 conversations, in both written and audio form, of both books have been extracted and analyzed by two raters. In order to assure agreement among raters, inter-rater reliability was calculated and showed a high correlation of 0.80. The results of this study were obtained by qualitative and quantitative analysis and they showed that native language authors use more variant CA strategies in their conversations.