The purpose of the present study was to investigate the effects of communicative activities in vocabulary learning. Based on the levels of processing framework proposed by Craik and Lockhart (1972), the following hypothesis was drawn: communicative activities were superior to non-communicative activities in terms of retention of learning items on the condition that time allocations would be the same in both activities. The same amount of time was allocated to both communicative and non-communicative activities, both of which were practiced in actual teaching of Japanese as a second language. The degrees of retention of newly introduced vocabulary were compared between the above two kinds ofactivities. Two sets of class time were set up to achieve the comparison. The results of both experiments showed that the retentions of newly introduced vocabulary in communicative activities were higher than those in non-communicative activities. These results supported the hypothesis based on the levels of processing framework for human memory.