Physical processes in the Gulf of Mexico (GOM) and mesoscale (10-300 km) processes associated with the Loop Current are fairly well known. However, little is known about the physical/ biological interactions of the frontal boundary system of the Loop Current. Zooplankton abundance and distribution was determined at 28 stations in the vicinity of the Loop Current. Species richness was high at all stations. Copepods comprised 60% of the total zooplankton collected. Oithona plumifera, Nannocalanus minor and Euchaeta marina were the most abundant copepods. Chaetognaths and ostracods were also very abundant and made up 11 and 5 % respectively of the zooplankton total. Total zooplankton abundance was higher at the boundary of the LC than it was inside the LC but not significantly different from abundances outside of the LC. Stations in the western Gulf of Mexico and on the western boundary had the highest abundances of zooplankton overall. The chlorophyll concentrations at the chlorophyll maximum were higher at the boundary of the LC than inside the LC. Physical-biological processes associated with the frontal boundary of the LC appear to influence the abundance and distribution of zooplankton in the GOM.