Reinforced Gore-Tex prosth eses were implanted into the t rac hea, above t he bif urcatio n, in 11 dogs. Th e firs t 3 anima ls d ied wit hi n a few da vs. du e to a n ina p propriate sur gical tec hniq ue. The remai ning animals were subjected to an adeqcate surgical proc ed ure and all su rvived-for a per iod 01 at least several mo nths, except one which died of an esc phaqo-t racheal fistula after 6 weeks. lngrowth of respiratory epit he lium into the prosth eses was obse rved 5 to 7 weeks postoperat ively.