The survey was conducted in the year 2019-20 to study the collar rot disease incidence in major brinjal grown areas of Tamil Nadu and to study the morphological character of Sclerotium rolfsii. The collar rot symptoms were identified and the sample were collected. Total 20 isolates were collected from different localities. It was conducted in the different localities of different district and plant disease incidence was calculated and hence morphological character of Sclerotium rolfsii was studied. The disease incidence recorded highest was in Kaveripattinam of Krishnagiri district which is 36.16 percent and followed by Vanur of Villupuram district which is 33.46 percent. The least disease incidence recorded was 7.73 percent in Kottur village of Theni district. The mycelium growth and no of sclerotia observed from different isolates were varied. The highest mycelium growth observed was 90mm and the least mycelium growth observed was 57mm.