Epinephelus morio (Red Grouper) is an important component of commercial fisheries for the United States and Mexico. Fishery-independent long-line surveys that utilized standardized sampling designs were conducted along the west Florida shelf, Florida and Campeche Bank, Mexico (2001–2002). Detecting true differences in abundance and sizes are difficult, but by using standard collection and aging methodologies, the level of bias was kept at a minimum. Relative abundance was higher in the Campeche Bank compared to the west Florida shelf (1.74 and 0.63 Red Grouper/100 hook hr, respectively). Fish from the Campeche Bank were also significantly smaller at length and weight. Differences in length, weight, and relative abundance of Red Grouper may be because of historical fishing pressure and management regulations, or the available carrying capacity of each area for Red Grouper. These differences have a substantial impact on how an overfished population can recover and be sustained.