Soil organic matter content is thought to be a soil quality index. The promoting effects of soil organic matter on soil physical, chemical and biological properties and eventually soil fertility has been widely accepted. The shortage of soil organic matter in arid to semi-arid regions of the world has lead us to enhance soil organic matter content by applying organic amendments. The applications of organic amendments improve soil structural stability, water holding capacity, permeability. This may also supply part of the plant nutrient requirements. The objective of this study was to assess the effects of different sources of the solid organic amendments on the kinetics of carbon dioxide evolution and N mineralization under standard laboratory condition. For this purpose, two calcareous soil samples were collected from Shervedan Research Station and Chamalishah located on the lower terraces of Zayanderoud river, Isfahan Province. An equivalent of 10 g kg -1 C of dairy cow manure, ship manure, poultry manure, gazelle dung, sewage sludge and municipal solid waste compost were separately added to the soils. A control treatment was also considered without application of the organic amendments. The treated soils were incubated in 50%water holding capacity and 25 °C for 31 days. The released carbon dioxide was measured periodically and the cumulative carbon dioxide emission was calculated. In a parallel experiment, another aerobic incubation was run for 90 days and mineralized N was measured by subtraction of the initial from the final inorganic N concentration. Results indicated that the trend of cumulative carbon dioxide emission versus time was conformed well to a first-order kinetic model. The cumulative amounts of C mineralized during the 30 days of incubation (Cm) ranged between 3908 to 7602 in Shervedan; and 3122 to 7256 in Chamalishah soil. The lowest and the greatest values of Cm were consistently observed in cow and poultry manure, respectively. The potentially mineralizeable C (C0) ranged between 4473 to 7544 in Shervedan; and 3655 to 7047 in Chamalishah soil. The lowest and the greatest values of C0 were observed in municipal solid waste and poultry manure, respectively. The initial potential rates of C mineralization (kC 0 ) ranged between 238 to 1056 in Shervedan; and 197 to 1057 in Chamalishah soil. The lowest and the greatest values of kC 0 were consistently observed in cow and poultry manure, respectively. Drawing the natural logarithm of C remained against time resulted in a two-phase degradation. The rate constant of the second phase (the lowest rate) were used to calculate the values of half life. The greatest and the lowest values of half life were observed for the cow and poultry manure, respectively. The cow manure half life was 56 and 81 days for Shervedan and Chamasalishah soil, respectively. The poultry manure half life was 25 and 28 days for Shervedan and Chamalishah, respectively. The greatest C mineralization rate was observed in the first week where the greatest and lowest rates belonged similarly to the poultry and cow manure. The cumulative amounts of C mineralized (C m ) were correlated with initial potential rates of C mineralization (KC 0 ). The correlation was time-dependent, such that it was increased during early 3 days and then decreased to the end of the incubation. The amounts of N mineralized during the 90 days of incubation were significantly correlated with cumulative C mineralized. The correlation coefficient increased during early 3 days and reached to somehow constant level and decreased after 11 days of incubation. We conclude that the optimum incubation time to obtain a precise estimation of N mineralization is 3 days following incubation. Key words : organic manure, carbon mineralization, nitrogen mineralization, first-order kinetics