In order to study the colonization of macroinvertebrates on the Rhizophora mangle roots, a short term in situ experimet was conducted between March and December 1989, at Bahía de Chengue, using mangrove stick as substrate and comparing their macroinvertebrate composition to the fauna associated to the mangrove roots. Most of the colonizing species were also associated to the roots; 80 species as a total appeared as colonizers: 35 crustaceans, 15 molluscs, 11 annelids, 10 cnidarians, 4 briozoan, 3 sponges and 2 chordates; 2002 specimens were counted, most of them (1757) crustaceans. The rainy season seems to favor colonization, since the highest values of diversity were measured then. Closeness to other habitats is a determinant factor for the arrive of organisms; this is shown by the similarity between the fauna associated to the mangrove roots and that colonizing the sticks in the lagoon, and the lower affinity between the roots,s fauna and that colonizing the sticks directly exposed to the sea.