The present work aimed to improve lavender plants (Lavandula officinalis L.) and volatile oil by using N fertilization and dry yeast in field experiment  during the two seasons of  2013/2014 and 2014/2015. Four rates of nitrogen fertilizer were used in this work; 0, 50, 100 and 150 kg/fed as urea (46 %N) combined with four dry yeast concentrations (0%, 10%, 20% and 30%). The results were recorded that vegetative growth (plant height, herb fresh and dry weights/plant), root system (fresh and dry weights of root/plant), oil yield (oil yield/plant and per fen) and some chemical constituents (N, P and K percentages). Generally the highest values of  vegetative growth and oil content per plant and per fed were obtained by using urea at level (150 kg.fed^-1) combined with spraying plants' leaves by 30% dry yeast as foliar spry under North Sinai conditions.