A completely automatic computerized technique for the quantitative estimation of the deamidation rates of any protein for which the three-dimensional structure is known has been developed. Calculations of the specific deamidation rates of 170,014 asparaginyl residues in 13,335 proteins have been carried out. The calculated values have good quantitative reliability when compared with experimental measurements. These rates demonstrate that deamidation may be a biologically relevant phenomenon in a remarkably large percentage of proteins.