This study was conducted to investigate the effects of different levels of humic acids on ruminal fermentation, protozoa count and some blood parameters in sheep. Four ruminally cannulated morkaraman rams, 1.5 years old, were used in 4X4 Latin Square Desing with 14 days adaptation and 6 days sampling periods on the way 20 days total. The animals were offered 70% forage and 30% concentrate supplemented with % 0, 0.1, 0.2 and 0.4 humate (Bovifarm (R)). Humic acid supplementation didn't effect the ruminal pH and ruminal ammonia-N (P > 0.05). Neither TVFA (Total Volatile Fatty Acid) concentration nor the proportion of acetic acid, propionic acid, butyric acid and acetic/propionic acid ratio in TVFA were affected by supplements. No differences were found among groups for protozoa counts (P > 0.05). In blood samples, there were no significant differences among levels for serum total protein, albumine, trigliseride, calcium, phosphorus and VLDL (Very low-density lipoprotein). However, all humic acids levels decreased (P < 0.05) the serum cholesterol and LDL (Low-densite lipoprotein); but increased (P < 0.05) the HDL (High-density lipoprotein) levels in groups supplemented with % 0.2 and 0.4 humic acids, significantly.