Electromagnetic waves traveling through the atmosphere experience an added phase shift due to the presence of various gases. Since the water vapor distribution in the atmosphere has a significant spatial and temporal variance, the corresponding phase shift can cause a serious degradation of the maps produced by radio interferometers. This study presents the calculation of the atmospherically induced phase shift in terms of ground based measurements and introduces a new technique to compensate for it. The compensation technique is implemented on the Berkeley-Maryland-Illinois Array at Hat Creek, California, and various tests are performed to demonstrate the accuracy of the technique. Finally, some future work is suggested. ¿ American Geophysical Union 1995