Examined the impact of repeated exposure to combat stress on 382 Israeli soldiers diagnosed with combat stress reaction (CSR) during the Lebanon War and on 334 non-CSR control soldiers who fought in the same units. CSR in the Lebanon War was related to the psychological outcome experienced in previous wars. The CSR rate in the Lebanon War was higher in Ss who had experienced CSR in a previous war than in Ss with no past combat experience. However, CSR rates were lower among Ss who had not had CSR in a previous war than among Ss with no prior combat experience. High intensity of combat in Lebanon increased both the detrimental and favorable effects of prior combat experience.