Examination of 349 Louisiana specimens of Sceloporus undulatus substantiates the presence of two subspecies in the state. Sceloporus u. undulatus inhabits areas east, and S. u. hyacinthinus areas west and north of the Mississippi- Atchafalaya river basin. The absence of specimens from the Mississippi-Atchafalaya river basin may indicate a lack of intergradation in Louisiana. In spite of extensive literature on taxonomy and distribution of Sceloporus undulatus (Latreille), little is known about the distribu- tion of the subspecies within Louisiana. Smith (1938), who last re- viewed this species in its entirety, recognized two subspecies in the state: S. u. undulatus in southeastern Louisiana, and S. u. fasciatus (= hyacinthinus fide Smith, 1948) in northwestern Louisiana. This conclusion was based on specimens from only three localities in north- western Louisiana; Smith had none from any other part of the state. Recent authors (Cagle, 1952; Conant, 1958; Keiser and Wilson, 1969) have accepted this Louisiana distributional picture. Smith (1938) distinguished the two subspecies primarily by mean differences in numbers of dorsal scales. Populations with a mean dorsal scale count of 36 or less were assigned to undulatus and those with 37 or more to fasciatus. My study was undertaken to determine the distribution and extent of intergradation of S. u. undulatus and S. u. hyacinthinus in Louisi- ana. METHODS AND MATERIALS. Three hundred and forty-nine lizards were ex- amined. Data recorded were sex, color pattern, snout-vent length, number of dorsal scales (DS), number of scales around the body (SAB), and number of femoral pores (FP). Scale counts were made according to the methods outlined by Smith (1946). Sex was determined by examination of the postanal scales, which are larger in males than in females.