The low rate of publications in internationally reputed scientific journals has become one of the main concerns of many Indonesian academicians and universities as these organisations are expected to contribute to knowledge and improve academic quality. One of the contributing factors is the researchers' mastery of English to write for international journals. This paper examines lexical density and reading ease of scientific papers, some of the indicators used for evaluating the quality of scientific writing. This study adopted three methods from Halliday (1985), Flesch (1948) and Gunning (1952) in determining the lexical density, fog index and reading ease. These three determining factors were then statistically calculated using simple regression; the results showed they have a highly significant effect (70.1%) on the standard of academic writing. Thus, it is highly recommended that Indonesian academicians enhance the quality of their scientific papers through the process of editing and proofreading prior to submitting their papers to international journals.