A mutual impingement of spray in a diesel engine was tried to assess the probability of further atomization of conventional diesel spray. The effects of impingement distance and impingement angle on the characteristics of the impingement spray were investigated by comparing with a nonimpingement free spray. In this study, the experiment was conducted for two typical impingement patterns, the jet-to jet impingement of liquid columns in the vicinity of the nozzles and the spray-to-spray impingement of fully developed sprays away from the nozzles. The spray tip penetration was reduced rapidly after the impingement in both cases of jet-to jet and spray-to-spray impingements with impingement angle of 90degrees. On the other hand, in the case of spray-to-spray impingement with 60degrees impingement, the penetrations were longer than that of free spray at just after the impingement. Spray tip velocity was calculated by differentiating the spray tip penetration curve. In the case of 90degrees impingement, the spray tip velocity was reduced rapidly by the impingement. However, in the case of spray-to-spray impingement with 60degrees impingement, the impinged spray had a tendency to increase instantaneously just after the impingement. This means that the spray may be accelerated by the mutual impingement. Atomization behavior was observed using a highspeed camera and it was found that the mutual impingement of diesel sprays caused the swelling of the sprays after the impingement. So, a simple model for estimation of impinging spray volume was proposed. The spray volume was about 1.5 times larger than that of free spray when the impingement distance was near the breakup point of the free spray. Also, the Sauter mean diameter (SMD) of the impingement spray was compared with that of nonimpingement free spray. The result showed that the SMD was slightly smaller compared with that of the free spray in the case of spray-to-spray impingement.