Current trends in the field of educational technology indicate a shift in pedagogical assumptions and theoretical frameworks that favor active involvement of self-directed learners in a constructivist environment. This study probes the influence of electronic portfolio evaluation on vocabulary learning of Iranian university students and the possible implications this influence affords. For this aim, the study recruited 66 students who were randomly assigned to the e-portfolio group and the traditional assessment group. The experimental group kept an e-portfolio in the intermediate level English language course while the traditional assessment group did not. The results revealed that the e-portfolio group outperformed the traditional assessment group in terms of vocabulary learning on the posttest. The results also showed that e-portfolio boosted students' motivation for learning new items. The perceptions of the participants in the e-portfolio group reflected that they benefited from the integration of technology and various educational activities and enjoyed keeping an e-portfolio. Finally, initial guidelines about how to use the instrument as part of the curriculum are discussed.