||A study of the relationships among multiple variables associated with exercise-induced oligo-amenorrhea in 70 healthy female runners, 18-37 years of age, was conducted. Seventy-seven percent of the runners were eumenorrheic while 23% were oligo-amenorrheic. The purpose of the study was to examine the relationship among serum lipids, body fat and ovarian hormones as well as re-examine other variables previously cited in the literature as being associated with exercise-induced amenorrhea, using multiple correlation and regression analysis. All participants completed a running and menstrual history questionnaire, the Schedule of Recent Experiences questionnaire, a four day diet diary, submaximal treadmill test, skinfold thickness, height and weight measurements and had two blood samples taken for analysis of estradiol, testosterone, progesterone and serum lipids. Analysis of the data revealed statistically significant zero-order correlations between the number of menstrual cycles per year and predicted maximum oxygen uptake, training time per mile, percent body fat, Nutrition;al intake, and serum estradiol levels. Multiple regression analysis revealed that only 12% of the variation in serum estradiol was explained by age, cholesterol intake, serum cholesterol, HDL cholesterol and percent body fat. A path analysis was utilized to explore possible causal linkages between variables of interest; 41% of the variation in the number of menstrual cycles per year was explained by the variables used in the path diagram. The mechanisms through which body fat, cholesterol intake and serum cholesterol affect the number of menstrual cycles per year remains to be elucidated.