This paper reports the in vitro degradability and fermentation of different amounts (0.25, 0.5 and 1 g 100 ml-1 of rumen fluid = RF) of five spices (cinnamon, cumin, coriander, turmeric and clove) alone or with rice straw during different incubation times. The main effects of spices were also considered for gas and methane production. Significant (P<0.001) differences were observed in in vitro dry matter degradability (IVD) and in vitro organic matter degradability (IVOMD) of spices and pH, ammonia and volatile fatty acids (VFA) of RF at 48 and 144 h. The IVD, IVOMD, ammonia and VFA were highest for cumin and lowest for cinnamon. IVD, IVOMD and pH were higher when smaller amount (0.25 g 100 ml-1) of spices were used (P<0.001). All the spices increased IVD, IVOMD, pH, ammonia and VFA at longer incubation time. The pH was lowest in turmeric. While VFA were greater for the larger amount of all spices, ammonia was greater for the larger amounts of only cumin and coriander. The molar proportion of acetic acid was lowest for turmeric. The gas and methane production was higher for the low amounts of spices where total gas volume was highest in turmeric and lowest in cinnamon (P<0.05).