The present study proposed to determine the influence of family structure and family size on basic-ideal disparity of males and females. The self concept scale was administered on the sample of 192 Science postgraduates to ascertain their basic and ideal self concept. The F values of the independent and interactional effects show the dominance of family size in the main effects. The interactional effects bring forth the salience of family size x sex, as well as, family structure x family size in determining the Basic-Ideal disparity.