Twelve inactivated oil adjuvanted vaccines (4 for EDS virus, 4 for haemophilus paragallinarum and 4 for bivalent vaccines) were prepared by using different ratios of Tween 80, span 80. Hydrophile-lipophile Balance (HLB) was determined for all vaccines. It was found that combined vaccine protected chicken against infectious coryza and egg drop syndrome (EDS) diseases with no interference between them in immune response of chicken. The vaccines that have HLB of 4.98 resulted in higher antibody titers more than those have 5.4, 6.01 and 6.58 HLB respectively.