An attempt has been made to correlate the rate and pattern of microbial degradation inside the tropical room with those observed in outdoor weathering exposures. Cotton dosootie, canvas cotton, cordages of jute, hemp, sisal and cotton, woolen fabric, rubberized fabric, leather (vegetable tanned), etc. have been exposed simultaneously in the laboratory tropical room and outdoors at Kanpur. Periodical observations have been made on the occurrence of microbial attack on these materials. Types of microflora and rate of degradation have been determined. The results enable us to predict the life of these materials when subjected to outdoor use by carrying out accelerated exposures inside the tropical room.