Experiments were conducted to study the viability and survival of uredospores of Puccinia arachidis, the groundnut rust in northern Kamataka during 2002-03. Studies indicated that, the uredospores were viable up to 20 days under field conditions (25-28°C) and optimum temperature of 25°C was found congenial for maximum germination. The humidity of 78 per cent was required for maximum infection and formation of more number of pustules. Groundnut plants of all age groups ranging from 10-90 days were found to be infected by uredospores. Further, uredospores on self sown/voluntary groundnut plants play an important role in survival and viability of the pathogen from season to season which help for perpetuation and carryover of groundnut rust in northern Kamataka.