A test chamber incorporating a remotely triggered low-light level video camera and recorder is described for evaluating food container resistance to damage by Norway rats (Rattus norvegicus). Data presented on the actual gnawing times necessary for a rat to penetrate a standard container and behavioral patterns associated with penetration suggest that this approach is a reliable measure of container resistance. To account for variation in penetration times both within and among test animals, we present a simple damage resistance index for test containers using a three-day test series to compare penetration times of test containers with an average of the penetration times for two standard containers. The mean index values derived in this manner appear sufficiently sensitive and reliable to rate the relative resistance of test containers. Application of this testing apparatus and method is described, including its limitations and possible modifications.