The infestation of twelve selected clones of alfalfa by the alfalfa seed chalcid was measured. The free sterol content of the stems, leaves, f lowers and pods of these clones was determined. A check was made to see if there was a correlation between the sterol content and the chalcid infestation. Differences were found among t he clones in the sterol content for each plant part. There were also significant differences in percent chalcid infestation in the 12 clones. Duncan ' s New Multiple Range Test pointed out which clones differed Significantly from the others. Using linear regression analysis, the correlation coefficient of the comparison between the sterol content and the chalcid infestation was obtained. There was a signtflcant negative correlation between the sterol content of the flower and the percent chalcid infestation. No significant correlation was found between t he sterol content of the stems, leaves or pods and the percent chalcid infestation.