A field experiment was conducted at the experimental farm of Faculty of Agric.; El-Mansoura Univ. during the winter season of 2011-2012 to investigate the various combinations among organic manures, growth regulators and biofertilizers on the production of safe and economic onion bulbs. Twenty four treatments were arranged in complete randomized block design with 3 replicates as follows; 1- Farmyard manure (FYM), 2- FYM + humic acid (HA), 3- FYM + cytokinin (CK), 4- FYM + yeast (Y), 5- Compost rice straw (CRS), 6- CRS + H.A, 7- CRS + CK , 8- CRS + (Y), 9- Compost town refuse (CTR), 10- CTR + HA, 11-CTR+CK, 12- CTR+Y. All treatments were studied twice; one in the presence of a mixture of multi strains inoculants and the other without it. Also, the recommended doses of N, P and K fertilizers for onion were put in consideration as a control treatment. Thus, the total numbers of treatment were 25 treatments. Results revealed that; the application of organic manures under investigation gained less vigor plant growth, total bulb yields and its components and nutrient content of onion bulbs as compared to the application of inorganic fertilizers (N,P and K at RD). Within the organic manure sources; the best parameters were attained by onion plants receiving CRS followed by that supplied with FYM and lately CTR. Inoculation of onion seedlings with the mixture of multi strains inoculants in combination with the growth regulators studied and the various organic manures under this investigation gave higher magnitude for all studied parameters than the application of organic manure alone. Moreover, such effect of this interaction gave, approximately the same values of inorganic fertilization for all the aforementioned traits.