To evaluate the use of scalar and vector Magsat data for the production of regional magnetic charts, comparisons have been made between charts of the north, east, vertical and total fields derived from Magsat with those derived primarily from Canadian aeromagnetic data. Approximately 12000 satellite data were reduced to sea-level using the spherical harmonic model MGST (4/81). Approximately 9900 aeromagnetic data from 1959 to 1976 were also reduced to sea-level and updated to 1980. All data were gridded at 1¿ intervals of latitude and longitude, and charts contoured. Good agreement exists between charts produced from the two data sets; the overall rms difference is 150 nT. The poorest agreement occurs in the north component. In all components the largest differences occur in the northern United States and along the east coast of Canada. Over the rest of the map area there are only a few large, randomly distributed differences.