this study investigates the cohesive devices used in the textbook of english for the students of psychology. the research questions and hypotheses in the present study are based on what frequency and distribution of grammatical and lexical cohesive devices are. then, to answer the questions all grammatical and lexical cohesive devices in reading comprehension passages from 6 units of 21units that are selected from the book, based on halliday and hasan`s model of cohesion (1976), are counted and their frequency and distribution also are calculated. the findings obtained from this study show grammatical cohesive devices in reading comprehension passages of the selected units are employed more than lexical cohesive devices. in this sense, it can be added that demonstrative references and additive conjunctions among other types of grammatical cohesive devices have high frequencies. in this study, ellipsis and substitutions in the units, because of very low frequencies, are excluded. considering lexical cohesive devices, it is observed that lexical reiteration items are more frequent than lexical collocation. regarding to the results of the study, it can be also derived that the author of the book follows a rather stable pattern in using and employing cohesive devices. for instance, the author always uses demonstrative references and additive conjunction with higher frequencies than other cohesive devices in the units. finally, some pedagogical implications due to the findings and results of the study are presented and also suggestions for further research are offered. key words: discourse, text, discourse analysis, cohesion, cohesive devices, esp approach.