Two field experiments (the first  one started  on 3/11/2010 and the second was on 3/1/2011) were carried out to investigate the. yield and quality of spinach as influenced by organic ( two levels: 0.0 and 15 m³  compost fed^-1), Bio. ( 0.0 , Microbine and  Nitrobine ) and chemical fertilization ( Four  levels; 0.0 , 50.0 , 100.0 and 150 % of recommended dose) at EL-Gawashna village, EL- Sharkia Governorate, Egypt. The possible combination between the studied factors levels represented 24 treatments The obtained results can be summarized in         Increasing mineral fertilizations from 0 – 50% led to a progressive increase in yield weight amounted by 20.649 % , while rising mineral fertilizations from 50.0 –100% led to a slight increase in that trait (0.856 %). 3.651 % increase in yield weight was noticed due to inoculation with both nitrobine and  microbine.          Using organic fertilization  decreased plant nitrate by 14 %. Spinach plant nitrate was decreased from 279.087 to 241.700 ppm as a result of Nitrobine fertilization and from 279.087 to 241.977 ppm as a result of microbine fertilization.         Increasing in spinach plant spinach nitrate was found concomitant with a constant increase in  NPK mineral fertilization dose.         spinach plant nitrite was statistically responded to both  compost application and bio- fertilization  where  statistically decreased in it's value compared with unfertilized treatment.         Organic fertilization tended to increase N content of spinach plant  under any studied mineral fertilization level ( 50, 100 and 150 % of recommended dose)          Inoculation of spinach seeds before planting by nitrobine and microbine increased N content of spinach plant by 5 % and 5%, respectively.         No evidence for superiority of any  inoculation than the other regarding to increasing the nitrogen content of spinach plant.        Compost effects did not appear on P content  of spinach plant, whenever  N P K  fertilization have done .         Inoculation maximized phosphorus content of spinach plant where neither organic nor  NPK mineral fertilization were added  than that under another conditions .        No difference in Phosphorus content  between nitrobine and microbine treatment means was found .       8- Phosphorus concentration was significantly increased with increasing N P K  fertilization level  till 100 % then decreased  after that (150 % of N P K )  .        A slightly  increase was found in K content  due to both  organic fertilizer  and   bio – fertilizer addition compared with no addition of each .