An in vitro bioassay is described that can be used for studying neurite growth, cell adhesion, and cell migration, as well as other cellular behaviors. The bioassay, which uses tissue sections as substrata for either dissociated cell preparations or explants, offers several distinct advantages over other commonly used bioassays. In particular, this bioassay approximates in vivo cellular environments, and the preparation of large numbers of tissue sections as substrata is relatively straight forward and simple. The method can be employed for studying cell behavior on different ages or types of tissue, as a bioassay for screening antibodies for their ability to perturb a particular cellular behavior, and for assessing the biological activities of growth factors absorbed to specific tissue environments. We present a detailed description of the method, including the variety of options to be considered at each step in the procedure, with an emphasis on using the assay to study neurite growth.