On the basis of the TOMS satellite column ozone data in latitudes 70¿S--70¿N from November 1978 to May 1990, we use a statistical model to estimate the trends in ozone as a function of latitude, longitude, and month. The trends in the TOMS ozone data are highly seasonal and dependent on location. Near the equator, the estimated monthly trends are not significantly different from zero. For high latitudes, most of the estimated monthly trends are negative. In January, February, and March there are some positive trend estimates in the western hemisphere around latitude 60¿N. The most negative trends for these 3 months also appear in the high latitudes of the northern hemisphere. Starting in June, more negative trends appear in the latitudes 50¿S--70¿S than the trends in the rest of the world considered. A large depletion develops during the spring time (September to November) in the southern high-latitude region, and the area of peak ozone decline is moving eastward during the period. The largest negative trends (about -29% per decade) for the area considered in this study appear in October around the latitude 70¿S and longitudes 20¿W--100¿W region. Since the magnitudes of the estimated trends in the southern hemisphere increase toward the pole, more negative trends occur beyond the latitude 70¿S. For the northern hemisphere, the year-round trend estimates for latitudes 30¿N--70¿N range from -0.96% to -7.43% per decade. In the latitudes 30¿N--50¿N, the winter trend estimates are more negative than those for the summer and the fall. However, this pattern did not hold for latitudes 50¿N--70¿N. ¿ American Geophysical Union 1992