The present study was carried out to investigate the effect of glucose that infused into rumen on ruminal pH. volatile fatty acids (VFA) and protozoa in two sheep that had been fitted with ruminal fistula. The study was conducted two period and each period contunied during 12 days. Feed was given to the animals once a day. Alter each feeding, sheep were rumınally infused with 500 ml (4. 2 ml/min) either deionized water (Period 1) or 40% glucose solution (Period ll). Samples of rumen contents were collected from each sheep before feeding, and 2h. 4h and 6h after tnfusion through the ruminal fistula. In the period t, ruminal pH and protozoa counts of sheep were found to be highest levels before feeding, compared with the levels of same parameters after feeding hours. Whereas, total VFA levels of sheep were determined to be lower amounts before feeding. Compared with the levels of same parameters in the Period I, the ruminal pH values, acetic acid levels, protozoa counts and proportions of Entodinium minimum were found to be lower amounts, but propionic acid level and proportions of lsotricha ipecies were higher in the sheep alter glucose infusion in the Period ll.