Lateral impacts of automobiles frequently result in abdominal injury to the occupants. While there have been important advances in the clinical management of this lateral impact trauma, the abdominal tolerance to injury from lateral impacts remains uncertain. The present report describes a series of 117 experiments in which the effect of changing the impact velocity and the forced abdominal compression upon the abdominal injuries sustained was monitored. The impact velocity was varied from 3 to 15 m/s, and the abdominal compression was varied from 10 to 50%. Serious injuries (AIS greater than or equal to 3) occurred in the following proportions of the total number of serious injuries: renal (54%), hepatic (44%), and splenic (1%). Impact side was a significant factor in hepatic and splenic tolerance, but not in renal tolerance. An abdominal injury criterion (AIC) is proposed which is a function of the impact velocity times the forced abdominal compression, but more work is necessary before it can be applied to human beings.