Objective: This study investigates the impact of musical activities on short-term memory in students with mental retardation. Method: In this experimental research, 26 fourth and fifth graded female students ageing from 12 to 19 years old (14.65± 1.67), educating in an exceptional children school in Shahr-e Rey, were assigned in two matched group. Then musical activities intervention including music and rhythmic movements were executed for the experimental group for 15 weeks and twice in a week. During this period the control group received routine educational program. Before and after intervention, the two groups short-term memory was assessed by digit span subscale of Wechsler. Results: t-test analysis showed that there is significant difference between mean difference of pretest and posttest scores of two groups (t = 4.233, P<0.0001). This means that the performance of experimental group was better than control group in posttest. Conclusion: This confirms that musical activities can enhance short-term memory in students with mental retardation.