Abstract: The current study included some physical and chemical properties at one location in the Euphrates River/North-Western of Baghdad and its relationship to the total count of algae and chlorophyll concentration to identify daily changes. The physical and chemical properties included the estimation of the temperature of air and water which was characterized by the height during the daytime and the decrease during the night, ranging between (17-26)^○C for air and (17-19)^○C for water. The values of the pH tended to the alkalinity by registering values above (7) and no daily changes appear clear. The electrical conductivity was the highest value (1310) μS cm^–1 and the lowest (743) μS cm^–1. The salinity values followed the values of electrical conductivity and ranged from (0.42-0.81)^○. CO₂ concentrations ranged from 1.51-3.62 mg L^–1 while total acidity reached values ranging from (755-6481) mg L^–1 and total alkalinity (214-367) mg L^–1. The results showed that there was no apparent decrease in the concentration of dissolved oxygen at the study site and did not reach complete depletion in station with the lowest concentration of dissolved oxygen in water (5.8) mg L^–1 and highest (7.8) mg L^–1. Plant nutrient ranged from (0.004-0.077) μg of nitrogen atom-nitrite/L while phosphate concentrations ranged (0.64-4.10) μg of phosphorus atom-phosphate/L and silica concentrations reached between (189-412) μg of silicon atom-silicate/L. (35) species of algae belong to (31) genus which the class in clued Bacillariophyceae, Cyanophyceae, Chlorophyceae, Euglenophyceae and Pyrrophyeae. As for the quantitative study, the total count of algae in the Euphrates river for samples studied ranged from (76×mn;10³) cell/L and (475×mn;10³) cell/L. Chlorophyll concentration was estimated in the river and the concentrations ranged from (5.43) μg chlorophyll-a/L at (16) o’clock and (0.91) μg chlorophyll-a/L at (24) o’clock.