One of the areas of toxicology in which a wide variation occurs in the statistical procedures used to analyze experimental data is behavioral toxicology. Due to either limitations in statistical training in the toxicologists or to a lack of understanding of the underlying biological mechanisms on the part of the statisticians, data is frequently analyzed by methodologies which either do not have optimal characteristics of sensitivity and power or for which the underlying assumptions as to the nature of the data are not valid. To establish a firm basis for an identification of the optimal and most appropriate forms of statistical analysis of behavioral toxicology data (and to design efficient and sensitive studies), the four general types of data (observational scores, response rates, error rates, and times-to-endpoints) and one special class of data (teratology and reproduction) are examined in detail. The present practices as to statistical analysis are then reviewed and suggestions as to optimal methods (based on experience, with data sets presented as examples) are developed and presented. The underlying key to this entire process is to establish the biological and statistical nature of the data being generated and to design and analyze experiments accordingly.