Nitrogen mineralization of soils under both aerobic and anaerobic incubation procedure and urea hydrolysis were studied under laboratory conditions. Percentage nitrogen mineralization potential (No) of total soil N was 30.0 under anaerobic incubation and about one‐half of that under aerobic conditions. Two different procedures were used to compute nitrogen mineralization potential. The determination using No= Nt/(l‐10‐kt/2.303) appeared time consuming whereas No= (factor ×?Nt/?t1/2) was found to be relatively quick for accurate prediction and could be used as a basis for Nodetermination in any area. The results of 2‐week incubation were remarkably similar to those for all other incubation periods with the aerobic or anaerobic groups. The hydrolysis of urea under flooded condition was found to be complete within 11 days.