This study was performed to determine the concentrations of creatinine (CRE), high-density lipoprotein (HDL), low-density lipoprotein (LDL), blood urea nitrogen (BUN), nitric oxide (NO), and malondialdehyde (MDA) in follicular fluid (FF) in relation to follicular size and/or stage of the estrous cycle [early I luteal (n = 14), early II luteal (n = 16), late luteal (n = 16), and follicular (n = 16) phases] in Anatolian water buffaloes. The concentrations of CRE (P < 0.001), HDL (P < 0.001), LDL (P < 0.05) BUN (P < 0.001), and NO (P < 0.01) in FF of large follicles (LFs, ?10 to <20 mm) during the early I luteal phase were lower than those of other stages. In FF of small follicles (SFs, ?5 to <10 mm), LDL and BUN concentrations were lower during the early I luteal stage (P < 0.05), whereas MDA levels were the highest (P < 0.001). MDA concentrations in SFs were higher than those in LFs during the early I luteal stage (P < 0.001). In conclusion, higher CRE, HDL, LDL, BUN, and NO activity in FF of LFs during luteal stages (early II and late) revealed that these biochemicals may play some roles in follicle development prior to domination and/or ovulation.