Modifications in a benthic community, induced by an experimental transplant of seagrass (Cymodocea nodosa Ucria), were studied in an area located in the southern basin of the Lagoon of Venice. Two surveys, carried out in March and September 1996, indicated that species composition and numerical dominants changed with season, with increasing dissimilarity between the transplanted meadow and the surrounding area. The latter was used as a control area and was characterised by the presence of pleustophytic algae (Ulva rigida, Gracilaria verrucosa, Chaetomorpha linum). Comparison with a natural C. nodosa bed showed that, only two vegetative seasons after transplant, seagrass performance and the structure of the macrobenthic community were quite similar to those recorded in a natural meadow. The experiment demonstrated the importance of C. nodosa transplant in the Lagoon of Venice and the changes induced in the whole benthic community by the introduction of seagrass in an area previously lacking it.