Nitrogen is the essential element of proteins, peptids, aminoacids, nucleic acids, chitin and peptidoglycans. It is also a macronutrient for plants which its uptake is relatively greater than other essential elements. Soil aminoacids contain both C and N and therefore, can be considered as a source of the elements for soil microbial population and a link between C and N cycles in soils. The aminoacid decomposition can be studied either by C or N mineralization. Carbon and nitrogen mineralization is functionally related and both are derived by soil microbial activities. More than 95% of total soil N is in organic form and aminoacids comprise between 20 to 40 % of soil organic N. These compounds are relatively easily decomposable and are subjected to rapid depletion from soils when the environmental conditions are favorable. A comparative study was conducted to investigate the C and N mineralization in soils received aminoacids as sources of C and N. For this purpose, different concentrations (0, 10, 20, 40, 60 and 100 mM) of L-glutamine, L-asparagine, L-histidine, L-arginine and glysine were applied to two Lavark and Shervedan soils with three replications. The mineralized C and N were measured during 6 and 24 h, respectively. To study the C mineralization kinetic, the carbon dioxide respired was measured at the concentration corresponds to the greatest C mineralization. N mineralization was also measured in aminoacid-treated soils as the soils werec applied with a 50 mM aminoacid concentration. Results indicated that both C and N mineralization was enhanced by aminoacid application, regardless of the aminoacid type. The optimum concentration was different in two soils. In Lavark soil, the greatest C mineralization rate for glucose was 100 mM whereas, the concentration for L-glutamine, L-histidine, glysine and L-arginine was 20 mM. The C mineralization rate in L-asparagine-applied soil was equal in 20 and 40 mM. The concentration for L-histidine In Shervedan soil, the optimum concentration for glucose, L-glutamine, L-histidine was 60 mM, while the concentration for glysine and L-arginine was 20 mM. The concentration for L-asparagine was eqally evaluated at 20 and 40 mM. A first order kinetic model was observed for C mineralization. The greatest C mineralization rate was observed at 15 to 60 min after aminoacid application, then it was increased decreasingly. In both soils, different aminoacids induced various kinetic constants. The greatest N mineralization rate was observed at 24 h following aminoacid application, followed by an either constant or decreasing rates. Moreover, the greatest N mineralization rate was observed at 100 mM. Overall, L-arginine induced greater amounts of N mineralization and no significant relationship was observed between C and N mineralized following application of the aminoacids.