This study attempted to analyze the psychological impact of mentally retarded children on their normal siblings in the family. The data were collected from siblings of 130 mentally retarded children using a questionnaire with a semantic differential scale. ANOVA and simple correlation coefficient tests were employed to examine the relationship between the siblings’ self-concept and psychological frustration. The major results of the study are as following. 1. Female siblings showed a lower degree of self-concept than male siblings. 2. No significant relationship was found between self-concept and frustration stimuli. 3. Parent related frustration stimuli was no significantly different in sex age, siblings, religion, and retardation level of mentally retarded children. 4. Siblings related frustration stimuli was significantly related to only one item in sex. 5. Their peers related frustration stimuli while sex as well as religion was significantly related to only one item.