Aims: The aim of this study was to identify and characterize the population of Enterococcus sp. in domestic wastewater as it flows through a constructed wetland. Methods and Results: Four hundred and eighty-four Enterococcus isolates were collected from the inlet, various sites within and from the outlet of a plastic lined constructed wetland in College Station, TX. The wetland treated septic tank effluent that passed sequentially through two 1 center dot 89 m3 septic tanks and a 1 center dot 89 m3 pump tank allowing 48 l doses at a 24 l min-1 rate. The Enterococcus isolates were identified to species using the commercial Biolog system. The 484 Enterococcus isolates were comprised of ten different species, including Enterococcus faecalis (30 center dot 6%), Enterococcus pseudoavium (24 center dot 0%), Enterococcus casseliflavus (12 center dot 8%), Enterococcus faecium (11 center dot 2%), Enterococcus mundtii (7 center dot 9%), Enterococcus gallinarum (6 center dot 2%), Enterococcus dispar (3 center dot 7%), Enterococcus hirae (2 center dot 1%), Enterococcus durans and Enterococcus flavescens both 0 center dot 8%. Of the 88 isolates collected from the inlet, only 9 center dot 1% of the isolates were identified as Ent. faecalis and Ent. pseudoavium (36 center dot 4%) was identified as the predominant species. Whereas of the 74 isolates collected from the outlet, the predominant species were identified as Ent. faecalis (29 center dot 7%). Species identification varied among sites within the wetland, but often Ent. faecalis was the predominant species. Conclusions: Our data suggest that while Ent. faecalis is the predominant species of Enterococcus found in domestic wastewater, the populations may shift during treatment as the wastewater flows through the constructed wetland. Significance and Impact of the Study: We found that shifts in Enterococcus species composition occurred during domestic wastewater treatment. This has implications for the identification of faecal pollution based on the presence of specific bacterial types associated with domestic wastewater.