Based on the assumption that B.A text-books may exert effects on the students’ writing, this study was conducted to investigate whether there was any relationship between the advanced EFL students' writing and their B.A course books or not. To this end, a sample of 35 first year M.A. TEFL students as advanced students and a collection of B.A. course books were selected. To set the criteria for comparison, we used a number of automated text easability indices that could measure difficulty level of both BA textbooks, and argumentative essays of about 500 words written within a time limit of at most 30 minutes by students at the beginning, middle, and the end of an advanced writing course. The essays and B.A course books were analyzed for syntactic complexity, word information, lexical diversity, referential cohesion, and connectives, using Coh-Metrix Text Easability Assessor. After analyzing the essays by Coh-Metrix, the results were subjected to statistical analysis. Generally, no meaningful differences were found in the mean scores of the two sets of texts and thus the target question was positively answered. That is, there was a direct relationship between the advanced students' texts and their B.A. course books although there were some differences in some indices which were not statistically significant. The results of the study can be used for effective teaching of foreign language writing, helping students to adjust their writing strategies to accomplish cohesion and coherence. Keywords: Writing; Coh-Metrix; Linguistic features; Language sophistication; Cohesio