This study investigated the efficacy of integrating SMS vocabulary learning into the Korean EFL classroom with low and high level students. The participants of the study consisted of 87 Korean university students and they were divided into four different classes (two classes for high level students and two classes for low level students). Within each level, one group was assigned to an SMS class while the other group was to a traditional class. The study compared the gained vocabulary scores between and within the groups according to instruction methods and different levels. The study also sought to determine whether there was a significant difference in perceptions and preference towards SMS vocabulary learning between low and high level students. The findings revealed that the SMS groups performed better than the groups who had received printed materials, regardless of students` proficiency levels. According to a survey, most of the students receiving SMS preferred this new method to learn English words. However, there was no distinguishable difference in the perceptions of mobile learning between the two levels. Based on the results of the study, pedagogical implications and suggestions for future research are discussed.