The bending characteristics of various brands of composite resins, which would represent the resistance against body fracture of resin restoration, were examined and the adequate indication of each material was detemined. The bending strength of heavily filled composite was generally greater than that of macrofi11ed and MFR type composites, and were nearly equal to that of amalgam. However, these materials remarkably decreased in bending bond strength at the junction of subsequently added composite resin. Bubbleless mixing slightly improved the bending strength of the chemically cured composites as compared with spatula mixing.