This paper reports on a study conducted to determine if comparisons between scores on the Test of English as a Foreign Language (TOEFL) and the International English Language Testing Service (IELTS) are justifiable. The test scores of 216 Iranian graduate students who took the TOEFL and IELTS, as well as the Iranian Ministry of Culture and Higher Education Test of English Proficiency (MCHE), from 1990-92 were compared. The study found high to moderate correlations between TOEFL and IELTS scores. Comparisons indicate that a score of 6 on IELTS is roughly equated with 600 on TOEFL, the minimum requirement for non-native speakers to gain admittance to most English-language graduate schools. A score of 6.5 on IELTS is roughly equated with 600 on TOEFL, the minimum requirement for non-native speakers to gain admittance to a linguistics department in most English-language graduate schools. The scores of the most proficient subjects on the two tests were found to be less comparable than the scores of less proficient subjects. An appendix contains a correlational matrix among subsections of the three tests. (Contains 23 references.) (MDM)