PIP: Numerous parameters of the chemical composition of porcine follicular fluid, obtained at different stages of follicle development, were analyzed. The concentrations of electrolytes, glucose, uric acid, selected enzymes, lipids, amino acids, cyclic AMP, and steroid hormones were determined and compared with concentrations in serum. There were both quantitative and qualitative differences in the composition of follicular fluid and plasma. These differences are discussed with regard to follicular development.