Abstract: A study was carried out in Periyar Tiger reserve and adjacent areas of Ranni, Konni and Achenkovil Forest Divisions in 1997 to collect information on herd composition, sex ratio, density and population of elephants. This area forms the portion of elephant reserve NO.1. The area mainly comprises tropical wet ever-green and grassland, followed by deciduous forests. Information on the herd size, composition and structure of elephants were collected through observations. The individuals were classified into different age categories. Line transact method was followed to collect information on dung density. A total of 379 elephants were sighted in 63 herds. Herd size of elephant ranged 1-19. About 14% were loners. Twenty-eight adult males sighted constitute 7.39% of the population. About 50% male were "Makhnas" and remaining tuskers in proportion of 1:1. Adult females formed 58.58% of the population followed by sub-adult females. The overall male to female sex ratio was 1:8.68 and adult male to female 1:7.93. The overall elephant density was 0.50/km2 in the study area and the density was comparatively higher in grasslands (0.89/km2).