The purpose of this book is to examine the interference errors of the students studying at the Department of English Language and Literature at Bingöl University,Turkey.Composition papers were analyzed and these errors were categorized as general errors and errors stemming from mother tongue (Turkish).The errors stemming from Turkish were initially categorized into four major categories; morphological, lexical, syntactic and orthographic and then those mentioned major categories were also divided into sub-categories. Finally, this book aims to propose suggestions to the researchers, foreign language teachers, and curriculum organizers which may help them to facilitate language teaching process, and also foreign language learners may become aware of their interference errors with the help of this study.