Frac packing has become the standard sand-control completion technique for many operators because of low completion failure rates and excellent production performance. These treatments are engineered to optimally place the stimulation fluids and proppants based on gravel-pack tool procedures and fracture model simulations. Direct near-wellbore measurements from radioactive (RA) tracers can be used to help minimize both the engineering and operational uncertainties of this process. The ultimate placement of the treatment stages pumped during a frac-pack operation is very valuable information. With this knowledge, the completion can be assessed in terms of productivity (including unwanted fluids) and reliability of sand control. A comprehensive review was conducted of 30 Gulf of Mexico frac-pack completions within four deepwater fields in which RA tracers had been employed. A general review of the spectral gamma ray logging process will be presented. Case histories will be presented that detail the utility of this technology in characterizing annular proppant voids, fracture growth successes and problems, channeling behind pipe, and operational problems.