Currently, over 117 species of grasses are used for turf, forage and erosion control, with new species being evaluated every year. Only a relatively few number of these species have been genetically transformed through biotechnology. With DNA biotechnological enhancement being considered for virtually all commercially important plants, the number of field-tests for transgenic plants are increasing exponentially. This trend is also happening with turf and forage grasses, with an increase in the number of new species being tested each year. Currently the following species have permit/notifications through USDA/APHIS to conduct field tests: creeping bentgrass ( Agrostis stolonifera L.); Kentucky bluegrass ( Poa pratensis L.); perennial ryegrass ( Lolium perenne L.); tall fescue [ Festuca arundinacea Schreber or Lolium arundinaceum (Schreber) Darbyshire]; Bermuda grass [ Cynodon dactylon (L.) Pers.]; Russian wildrye [ Psathrostachys juncea (Fischer) Nevski]; Bahiagrass ( Paspalum notatum Flügge var. saurae Parodi); Kentucky bluegrass x Texas bluegrass ( Poa pratensis x P. arachnifera Torrey); St. Augustine grass [ Stenotaphrum secundatum (Walters) O. Kuntze]; and velvet bentgrass ( Agrostis canina L.). The significance of gene escape will vary with the biology of the plant donor, the wild recipient, and the introduced gene(s). In regards to the crop donor, primary risks will probably come from crops: 1) that have undergone little domestication because there would be minimal ecological and reproductive divergence from the wild progenitors (Ellstrand and Hoffman 1990); 2) grown sympatric with wild relatives (e.g. centers of origin) or crosscompatible species (or genera); 3) that have biotypes or related taxa that are already aggressive weeds; 4) that can also be weeds themselves; and 5) outcross with some degree of self- incompatibility. Because of the large number of grass species used for turf and forage, and since the potential for gene escape and its consequences will be different for each species or species complex, only those taxa currently in the APHIS Field Test program will be discussed at this time. What is known biologically and systematically about each taxon, and the complexes they form will be presented.