Rumen fermentation pattern of sheep was greatly affected by several factors. This investigation was conducted to evaluate the effect of seasons and digestive disorders on rumen physical, cellular, biochemical constituents and rumen fermentation efficiency in Egyptian sheep. A total number of 97 native breed sheep were classified according to clinical presentation into apparently healthy 58 and clinically diseased 39. The apparently healthy sheep were divided according seasons into: autumn 15, spring 16, summer 17 and winter 10. Diseased sheep were suffering clinically from different digestive disorders; simple indigestion 19, rumen acidosis 12 and rumen alkalosis. All animals were subjected to detailed case history, comprehensive clinical examination and rumen liquor sampling for analysis. Obtained results revealed that autumn had significant increase in pH and acetic acid with significant decrease in TPC, Epidinium, NHs-N and calcium. Winter had significant increase in Epidinium, TPC, lactic, butyric acids, calcium and magnesium with significant decrease in Entodinium. Spring had significant increase in ALT and GGT activities. Summer had significant decrease in TVFAs, lactic, butyric acids, CH4 and magnesium. Sheep in spring and winter seasons had better rumen fermentation efficiency than sheep in autumn and summer. Simple indigestion, rumen acidosis and rumen alkalosis were common digestive disorders affecting Egyptian sheep causing significant changes in rumen liquor constituents. Simple indigestion had highly significant increase in Diplodinium with highly significant decrease in TPC. Rumen acidosis had highly significant increase in Entodinium, TVFAs, propionic, acetic acids, FE %, calcium and magnesium with highly significant decrease in pH, TPC, Diplodinium, Epidinium, Holotricha, NH3-N, A/P ratio, CH4/TVFAs % and AST activity. Rumen alkalosis had highly significant increase in pH with highly significant decrease in TPC, TVFAs, lactic, propionic, butyric, acetic acids, CH, calcium and magnesium.