Our study aimed at finding out the effectiveness of corpus-based vocabulary teaching activities as well as students' attitudes towards concordance-based materials when corpus-based tasks in English vocabulary learning are used. The study was conducted in a preparatory school in a private university. The participants were 28 intermediate level students whose native language was Turkish and they were between the age of 17 and 20. They were placed into two intact groups as experimental and control group as a result of a pre-test. While the participants in the experimental group were taught through corpus-based vocabulary teaching activities, those in the control group were taught vocabulary activities through the tasks in their text book and dictionary. The data were collected through a proficiency exam, pre- and posttests and a 12 item-questionnaire based on a 5-point Likert scale as quantitative instruments and through interviews and learner diaries as qualitative instruments. The quantitative data were analyzed through descriptive analysis and independent samples t-tests, and qualitative data were analyzed through content analysis by observing themes in students' responses during the interviews and learner diaries. The statistical analysis indicated that using corpus-based vocabulary tasks were more effective than the tasks in the textbook. Additionally, our findings indicated that the attitudes of the students were positive in the use of corpus-based vocabulary tasks.