The bond strength and wood failure values of resins made with different additions of cornstarch 5:95, 7:93, 10:90 and 13:87 (cornstarch–UF, weight ratios) was tested and compared with that of a control UF resin (0:100) at 1958C and 4 min press time. The results of the effect of corn-starch substitution level on the bond strength are shown in Table 1. With the increase of cornstarch substitution level, the bond strength and wood failure appeared to be rela-tively unaffected by the presence of cornstarch up to 10%(10:90) and then decreased. Furthermore, the test revealed that in most cases, joint failure was cohesive in the wood (wood failure) and not due to failure either at the interface or of the adhesive itself. It is interesting to note that, when the substitution level was higher than 10%, resin showed 16% reductions in bond strength values compared to wood strips bonded with control UF resins. It is concluded that substitution level of 10%is optimal for the preparation of cornstarch–UF wood adhesives.