The present study adds to the computer-mediated communication (CMC) literature by exploring oral learner-to-learner interaction using Skype, a free and widely used Internet software program. In particular, this task-based study has a two-fold goal. Firstly, it explores possible differences between two modes of oral CMC (audio and video) and traditional face-to-face (FTF) interaction in terms of L2 vocabulary development. This study also investigates participants' perceptions regarding these computer-mediated modes of communication. A within groups experimental design was employed in which a total of fifty-eight third semester college students of Spanish participated. Twenty-nine conversational dyads were assigned to one of three different groups: face-to-face, video CMC, and audio CMC. Repeated measures ANOVA analyses were conducted on the scores of the final pool of participants (N=47) in production, recognition, and aural comprehension tests to investigate possible differences. Furthermore, descriptive analyses were carried out of participants' answers to a debriefing questionnaire that tapped into their perceptions toward these CMC modes. Results showed no significant differences among the groups for production or written recognition measures. All participants, however, were able to retain their recognition ability (but not their production ability) after two weeks. Finally, a significant difference was found among the groups in aural comprehension measures: the audio CMC group outperformed both other groups. Regarding participants' attitudes toward the CMC modes used in this study, they had generally positive attitudes, which may be exploited in the L2 classroom. (Contains 5 tables, 6 figures and 3 excerpts.)