A brief description of the Gulf underwater gravimeter is presented showing the salient design features whereby a regular Gulf gravimeter is incorporated in a device permitting precision gravity measurements in coastal waters several hundred feet in depth. The instrument is adapted to be lowered to the bottom on a cable and through remote control devices all necessary adjustments are made from the surface. The reading is obtained photographically on a continuously moving film which permits accurate observations even when moderate seismic disturbances cause oscillation of the index point.