Sweet basil, Ocimum basilicum L. is an important medicinal plant, has been used in various uses. The productivity of basil plants of fresh, dry herb and its chemical constituents were determined at two locations in Egypt (Toshka in the south of Egypt and Baloza in the north of Egypt) during the two seasons (2011-2012) to investigate effect of location on the yield and chemical constituents of plants. The obtained results indicated that Baloza location gave the highest significant values of fresh, dry herb and essential oil yield per plant and per feddan , while Toshka location gave the lowest values. The percentages of consequently oils, carbohydrates, nitrogen, protein, flavonoids, alkaloids, phenolics, terpenoids and vitamin C contents reached their maximum values (0.355, 9.03, 0.17, 1.06, 0.73, 0.265, 1.81, 3.56 and 2.065% respectively( in the plant samples collected from Baloza location, while the percentages of total ash and total lipids reached (15.42 and 1.875 % respectively). The mean value of the elements Phosphorus, Potassium, Sodium in the plant samples at the two seasons were higher at Toshka location. By using GC/MS,  essential oil composition differed between the two locations. Estragol (54%) was the major compound in the oil of Toshka location. Meanwhile, linalool (45.62%) and estragol (37.22%) were the main components for the oil of Baloza location. The results of this study revealed that Ocimum basilicum growing in Baloza and Toshka locations are a good source of phytochemicals and nutrients ,which can be used in various pharmacological and industrial purposes, but the environmental conditions of Baloza location were more suitable for the growth , yields and chemical constituents than that of Toshka location .