With increasing numbers of international students enrolling in universities in English speaking countries such as Australia, the question of the level of English language proficiency (ELP) necessary for academic success becomes critical. The main question for this study was the usefulness of IELTS and TOEFL (the two main measures of ELP used for selection to universities in Australia) respectively as predictors of readiness for the Australian academic context. However, earlier research suggests that ELP is only one of a number of factors impinging on academic success (Davies 1990; Criper & Davies, 1988). This study was, therefore, also concerned with additional factors which may influence academic progress, such as the effect of English language support. The research was carried out at the University of Melbourne. Data for the study included students' IELTS and/or TOEFL scores and Grade Point Average as well as questionnaire and interview data. The relationship between GPA and IELTS scores was found to be moderately strong whereas the correlation between achievement and TOEFL score was relatively weak. These results appear to be consistent with the results of previous studies. In the interview and questionnaire data students identified non-linguistic factors affecting their academic performance which may help to explain the weak correlations between ELP score and academic success.