Conventional intercomparisons between absolute gravity meters are limited in accuracy by the difficulty of removing environmental signals, including effects such as Earth tides, ocean loading, and barometric pressure loading. These error sources can be eliminated completely through the use of exactly simultaneous measurements. Differencing techniques have been developed and tested which are capable of determining both the differential meter bias and the gravity difference between two nearby piers to an accuracy that is limited only by the instrumental noise. Preliminary tests show that a comparison accuracy of 0.3 &mgr;gal may be obtained in less than 400 drops, independent of drop interval (1 &mgr;gal=10 nanometer/sec2). ¿ American Geophysical Union 1996