The present study was an attempt to examine different areas of gender-bias in representation of women and men in 3 volumes of English textbooks taught in the high schools of Iran. Chi-squares were performed to find the frequency of names, nouns, pronouns and adjectives attributed to women and men. Also, chi-square was carried out to investigate whether women and men had more or less equal first-place occurrences in instructions, exercises and sentences. Furthermore, the other areas which were investigated were: 1. reading passages to find whether women and men appeared more or less equally or not, 2. male-generics and 3. animals. The findings revealed that the manifestation of women and men in these textbooks was not fair. In other words, the presence of men was more highlighted than that of women regarding names, nouns, pronouns and adjectives attributed to them. In regard to firstness, also, male-attributed terms came first more frequently than those of females. In reading passages, male characters appeared more frequently than female characters. Moreover, these textbooks contained many male-generics in which women were almost invisible. Also, sexism was detected in regard to animal representations. {\textcopyright} 2010 Published by Elsevier Ltd.