Nowadays, there are a large number of teaching and learning techniques and programs designed in order to improve EFL learners’ vocabulary competence. 90% of the people on earth have mobile phone network, and 41% of users have more than one mobile device. Moreover, these electronic devices play an increasing role in educational programs. This study was intended to examine the impact of using short message service (SMS) on Iranian EFL learners’ incidental and intentional vocabulary acquisition. In order to fulfill the intended objectives, 40 intermediate learners studying English in an Institute were chosen. The participants were divided into incidental and intentional groups. The participants were presented with a pre-test one week prior to the provision of SMS trend and a post-test after that. Interpreting the obtained results, it was concluded that the intentional group could learn more vocabulary than the incidental group. In addition, a questionnaire was provided to the participants to check their satisfaction with the trend. It was revealed that the students were highly motivated learning the second language using Mobile-Assisted language Learning (MALL).