A number of widely different animal seizure models have been employed in the search for new and novel anticonvulsant drugs useful for the treatment of human epilepsy. At present, no single laboratory test will, in itself, establish the presence or absence of anticonvulsant activity or fully predict the clinical potential of a test substance. Of the many available animal models, the maximal electroshock (MES) and subcutaneous pentylenetetrazol (scPTZ) tests still represent the most commonly employed models for the routine screening and identification of new anticonvulsant drugs. This chapter will briefly describe how these two tests are conducted, their limitations and how they have contributed in the past and to the present day anticonvulsant drug discovery process.