This study was an attempt to investigate the effect of input enhancement instruction on vocabulary acquisition among Iranian university students. Moreover, the possible effect of two kinds of input enhancement (i.e., auditory and visual) was examined. To this end, 75 Iranian university students, majoring English language Teaching at Applied Science and Technology of Kurdistan University, Iran, were randomly selected. The method used in this study was quantitative research and the true experimental design. One experimental group received vocabulary instruction via visual input enhancement, and the other experimental group was taught vocabulary via auditory input enhancement. After administering the posttest, the dada was analyzed by one-way ANOVA. The findings revealed that both auditory and visual input enhanced instruction had a significant effect on the vocabulary development of Iranian EFL students. In addition, comparing the efficacy of two types of instruction, the results indicated that the effect of either visual or auditory input enhancement for both experimental EFL university students were fairly the same in Iranian EFL educational setting.