This study aims to investigate the effect of using concordances and word processors on EFL graduates' performance in academic writing. To achieve this aim, the subjects were asked to use linguistics corpora and word processors to correct their grammatical and spelling mistakes in their written papers in a course that lasted for sixteen weeks. The sample of the study consisted of 48 MA students. Quantitative and qualitative measures were used to gain possible results of the effect of using concordances and word processors on the learners' achievement and performance in writing. Ratio gain relations were estimated, too. To find the participants' achievement, pre- and post-tests were used; semi-interviews and answers to a questionnaire were also analyzed to investigate their attitude toward using concordances and word processors in writing. The findings indicated that their performance improved due to the effect of using concordances; however, spelling and grammar word processor had a slighter effect on their achievement. Recommendations were included for further research.