Distribution patterns are defined for the caridean shrimps of two estuarine systems of the southwestern Gulf of Mexico, Laguna de Terminos and Laguna Madre. The patterns include a "wide" (W) and a "restricted" (R) distribution with respect to the presence of each species along a salinity range, as well as an "associated with the habitat" (AH) and a "not associated with the habitat" (NAH) component defined with respect to the presence of a species in one or more types of habitat. Specimens collected were 12,176 of I I species in Terminos and 1,617 of nine species in Madre. Hippolyte zostericola was the dominant species with 85% and 54% of the total density in Terminos and Madre, respectively. Over 80% of the density of carideans in each lagoon and 55% and 72% of the species richness in Terminos and Madre, respectively, were found in habitats with submerged aquatic vegetation. Laguna de Terminos has five RAH species associated with submerged aquatic vegetation (SAV) in euhaline environments, two WAH species associated with SAV, and three WNAH species with no habitat preference. Laguna Madre has two RAH species associated with SAV in euhaline habitats, one WAH species in SAV in all localities, and three WNAH species in all types of habitats. These caridean patterns agree with those registered for the brachyuran crabs of Laguna de Terminos. Two faunistic groups and two guilds were determined for each lagoon. It is concluded that both crabs and shrimps may be used as indicator species for particular environmental characteristics and types of habitat.