Artificial aging experiments were done to investigate the ability of boot leather to withstand exposure to tropical climates. Samples were aged in chambers at 20, 30 and 40°C over water for 8 and 16 weeks; ball burst strength, tensile strength and stitch tear were measured. Chemical analysis was done to determine pH, % moisture, grease, hide substance, total ash, chrome, water solubles, insoluble ash, vegetable tannin, combined tannin, degree of tannage, and paranitrophenol. Mold grew on all samples except the chrome-vegetable retan leather, which contained para- nitrophenol (p-nitrophenol; merthiolate was also tested and prevented mold growth and a decrease in grease content and in pH). Chrome-vegetable retanned side leather with stuffing grease shows the greatest breakdown when aged at 100% relative humidity (RH) and at 40°C. Straight chrome tanned leather and fatliquored straight vegetable tanned leather show less degradation. Deterioration occurs independent of mold growth on the leather. Decrease of strength on aging is independent of a decrease in grease content. The lengthy discussion following the presentation is included in the article.