This study compared lipoprotein phospholipid, cholesterol, protein, and glycosaminoglycans in the lipoprotein fraction among follicular fluid pools derived from 2633 small (less than 6 mm), 1702 medium (6 to 10 mm), and 491 large (11 to 20 mm) bovine follicles subdivided by estradiol-17 beta concentrations. High density lipoproteins were the only lipoprotein class found in follicular fluid when apolipoprotein profile of the less than 1.21 g/ml density fraction was analyzed using sodium dodecyl sulfate polyacrylamide gel electrophoresis and silver staining. Within a follicular size class, concentrations of lipoprotein constituents did not change among follicular fluid pools with varying estradiol-17 beta concentrations. As follicular size increased, follicular fluid lipoprotein phospholipid, cholesterol, and protein significantly increased. The percentage of total follicular fluid glycosaminoglycans in the less than 1.21 g/ml density fraction was highest for small follicles but averaged less than 5% for all follicular size classes. Therefore, bovine follicular fluid contains only high density lipoproteins and concentrations increased with follicular maturation. That increase in high density lipoprotein could be a potentially important source of cholesterol for progesterone production after the LH surge.