A sandwiched type of electrogalvanized (EG) steel sheets bonded with poly(vinyl butyral) (PVB) was used to study the effect of chromate conversion coating on the interfacial bonding and bending formability of the laminate. It was found that a proper chromium passivation on the steel surface enhanced both initial tensile shearing strength (TSS) and the joint durability in the corrosive environment. The greatest TSS, i.e. 17.8 MPa, was measured for the chromated steel sheet with chromium content ranging 0.040-0.055 g/m(2). A good correlation between the TSS and the bending formability of the laminate was obtained. Poly(acrylic acid) (PAA) was also added in the chromate solutions and the complex conversion coating exhibited an improvement on the shearing properties of the EG steel sandwiches. The effect of PAA incorporated in the chromate coating on adhesion was dependent upon its concentration and molecular weight. The greatest TSS, i.e. 24.0 MPa, was measured by adding a proper amount of PAA with MW = 380,000 g/mol, approximately 8 wt %, in the chromate solution for EG surface coating. The possible mechanism of the enhancement of interfacial properties due to the incorporation of PAA will be discussed.