In order to clarify technical problems in evaluating neurotoxicity of chemicals and to solve them, a collaborative study with a common protocol was conducted at 11 domestic safety research laboratories. In the collaborative study, acrylamide and IDPN (3,3'-iminodipropionitrile), which are known neurotoxicants, were used, and the chemicals were orally administered to rats for 28 days. In addition to the clinical observation done routinely, detailed clinical observation, sensory and motor function tests including grip strength and motor activity were performed to evaluate neurobehavioral toxicity with reference to Functional Observational Battery (FOB). In general, neurobehavioral toxicity of the two chemicals was detected in the collaborative study. However, we also encountered technical problems, since neurobehavioral testing was unfamiliar to us. In the present report, we describe the major problems and how to solve them, and briefly explain the neurobehavioral testing procedure.