This paper studies the effects of the war on the civilian and military Lebanese populations from 1975 to 1987. A review of the literature on war psychiatry is presented as an introduction in order to estimate its applicability to Lebanon, and it seems that all the morbid conditions described in the different wars are to be found in Lebanon. A study on the military population was undertaken, focusing on the comparison of the morbid conditions before and during the war. It shows that war has led to a decrease of malingering and generalized anxiety disorders but to an increase of neurotic and psychotic reactions. A comparison of these conditions with those found in Vietnam shows a greater proportion of generalized anxiety disorder and PTSD among Marines in Vietnam. The militia members of the Lebanese Forces differ from the Lebanese Army soldiers by a higher proportion of antisocial personality disorders and anxiety neuroses. Among the civilian population war does not seem to have significantly modified inpatient morbidity in the main psychotic, affective and neurotic diagnostic categories. Drug abuse, whose frequency has considerably increased during the war, is studied in detail. In conclusion, the author analyzes the factors having contributed to the relative psychological resistance of the Lebanese population.