A study was conducted to evaluate selected chemical methods for assessing the availability of organic soil nitrogen in Mississippi soils using nitrogen mineralized by aerobic and anaerobic incubation under controlled conditions as standards for comparison. Sixty-two soil samples were collected from agricultural and non-agricultural sites in representative physiographic areas of Mississippi. The soils varied greatly in texture, pH, management practices, and organic matter content. The chemical methods evaluated were: organic matter (M1) ; total nitrogen (M2) ; Ca(OH)2 hydrolysis (M3); initial inorganic nitrogen (M4); exchangeable ammonium (M5), autoclaving and washing with 1 M KCl (M6); autoclaving and washing with 0.01 M CaCl2 (M7) ; autoclaving in 0.01 M CaCl2 and washing with 1 M KCl (M8); Walkley-Black nitrogen (M13) ; alkaline permanganate digestion (M14) ; and ultraviolet absorption (M15). The biological methods, used as standards for evaluation of the chemical methods, were: aerobic mineralization - 1 week (M9); aerobic mineralization - 2 weeks (M10); aerobic mineralization - 1 week plus 2 weeks (M12); and anaerobic mineralization 3 weeks (M11). Except for initial inorganic nitrogen (M4), exchangeable ammonium (M5), and ultraviolet absorption by NaHCO3, soil extracts (M15), all the chemical methods were moderately to highly correlated with each other, and, therefore, may be divided into two groups: the autoclaving methods (M6, M7, M8) and the other methods (M1, M2, M3, M13, M14). The highest correlation obtained with the chemical methods was between total nitrogen (M2) and Ca(OH)2, hydrolysis (M3). Of the chemical methods only initial inorganic nitrogen (M4) and exchangeable ammonium (M5) were not highly statistically correlated with the biological methods. The chemical methods were correlated to a lower degree with aerobic mineralization by M10 than with other biological methods. Based on degree and consistency of correlation, the chemical methods were ranked numerically as to their effectiveness in the following order, from simple correlation analysis: Ca(OH)2 hydrolysis (M3) > total nitrogen (M2) > alkaline permanganate digestion (M14) > Walkley-Black nitrogen (M13) > autoclaving procedures (M6, M7, M8) > organic matter (M1) > ultraviolet absorption by NaHCO3 soil extracts (M15). When the C:N ratio was included with the biological methods in a multiple regression analysis, only the effectiveness of organic matter was increased substantially. Consequently, the order of effectiveness as established by simple correlation analysis was unchanged except that of organic matter (Ml) that was brought among the chemical methods having the highest correlation with the biological methods.