In an attempt to facilitate and foster idiom retention and recall, this study investigated the effect of pictorial and etymological treatments on Iranian undergraduate students' idiom learning. The paired-samples experimental design was used to study 26 students who had registered for the Use of Idioms course at the University of Bojnord (UB). One hundred target idioms were selected from 50 programs of the VOA's Special English (Words and their Stories). Half of them were taught accompanied by funny pictures and etymological elaboration and the other half were taught without any pictures. After the treatment, the subjects were given an immediate posttest and a delayed posttest one month later. The reliability of the 40-item posttest was estimated at 0.83 through the KR-21 formula. The data obtained was analyzed using paired-samples t-test. The results of data analysis indicated that the differences between the two conditions were statistically significant in both immediate and delayed posttests. The findings imply that the pictorial-etymological treatment was more effective than etymological treatment only.