The main object of this study was to determine the effect of plant density and some vitamins and active yeast on essential oil production and some chemical constituents of sweet basil. The experiment was conducted during two successive seasons of 2014 and 2015 at the ornamental laboratory and nursery, Fac. Agric., Minia Univ. Results showed that by increasing plant densities. The oil production decreased/plant and increased/fed. Also, the lower density increased pigments and NPK % elements. All used vitamins and active yeast treatments increased essential oil production (oil % and yield). The collection of vitamins increased essential oil % and pigments content, while active yeast treatment increased essential oil yield and the percentages of N, P and K %. The best interaction treatments for essential oil production/plant were two higher plant distance (80 and 65 plants/14.5 m²) in combination with active yeast or 65 plants/14.5 m² × vit. B₁ + vit. C + vit. E. While, the highest yield of essential oil/fed were obtained with higher plant density (145 plants/14.5 m²) in combination with active yeast or vit. B₁ + vit. C + vit. E.