A study investigated the hypothesis that topic familiarity and assessed difficulty of a second language text correlated positively with performance on reading comprehension tests in languages for special purposes (LSP). Subjects were 177 advanced students of English as a Foreign Language (EFL) at Ben Gurion University (Israel). Faculty from the schools of Humanities and Social Sciences (HSS) and Science and Technology (ST) were asked to assess the difficulty of an HSS-related text and a ST-related text from a college-level EFL reader. The texts were found to be of comparable difficulty and comprehensible to an educated layman. Students then took a reading comprehension test using the passages, and were asked to evaluate the passages' difficulty. Significant interaction between faculty and assessed difficulty of text confirms that EFL students find texts related to their fields of study more comprehensible than texts related to other topics. However, results of multiple-choice comprehension questions based on the texts indicate that students' subjective evaluation of the relative difficulty of a text is not necessarily a reliable predictor of their actual performance on reading comprehension tests. Based on these findings, it is argued that creation of many different reading tests on specialized topics at the university level is not justified. A 24-item bibliography and tabulations of study results are appended. (Author/MSE)