A catalog of shallow earthquakes (depth ≦ 65 km) of Mexico (15° to 20°N, 94.5° to 105.5°W) covering the period 1900 to 1981 is presented. The catalog includes only those events whose magnitudes (M, Ms, or magnitude from Pasadena) are ≧5.9. It is most likely complete for shocks with Ms ≧6.5 from July 1906 to December 1981. For many shocks, Ms has been determined from Uppsala bulletins and/or Uppsala and Göttingen Wiechert Seismograms. The statistics of incremental frequency n(Ms) shows a peak at Ms ≃ 7.7, reinforcing a previous observation by Singh et al. (1981). In the range 6.4 ≦ Ms ≦ 7.5, the observed n(Ms) deviates significantly from an exponential distribution. The catalog provides a basis for further statistical analysis of earthquakes in Mexico.