Spilled oil into marine environments are known to induce disturbance not only hepatodetoxification system but also immune function in fish. However, toxic mechanisms on immune system and complex toxicity of crude oil have not been fully investigated. Innate immune response considered on the attractive effect-based monitoring tools due to their capacities to predict population disturbances by modification of disease susceptibility. In the study, to clarify the toxic effects of Hebei sprit spilled crude oil on fish immune system, multiple hepatodetoxific enzymes (Cytochrome P4501A and GST) and cytokines such as Interleukin-1beta (IL-1β), granulocyte colony-stimulating factor (G-CSF) were evaluated in juvenile Rockfish fed individually the gelatin-capsulated Iranian Heavy Crude Oil (IHCO). At 12 h after treatment, the oil-fed groups were shown higher concentrations of biliary 1-OH pyrene fluorescence metabolite and CYP1A expression than the control group. Cat. L and G-CSF mRNA also increased significantly at initial stage of exposure (from 12 h to 48 h after exposure) but decreased to the level of control group or less. 72 h post-oil injection, fish were intraperitoneallyadministered an LD50 dose of Streptococcus iniae (FP.5228; Korea Fish Diseases Information Center). Host survival was monitored for 7 days and cumulative mortality rate was calculated. Host mortality rate was increased significantly in oil exposure group compared to sham group.