Experiments were conducted in nine New Zealand White rabbits to determine the functional capacity of that part of the oviduct consisting of only the isthmus and proximal ampulla. The left fimbria and at least one-half of the adjoining ampulla were excised microsurgically and the remaining portion of the proximal ampulla was subjected to a cuff salpingostomy. Following a convalescence of 4 to 8 weeks and gonadotropin-induced ovulation, direct observations in vivo showed tht the modified oviduct was ineffective in transporting surrogate cumulus masses into the tubal lumen. Those surrogates that were accepted were in some cases regurgitated by contractions of the residual proximal ampulla. A subsequent in vitro search for ova proved that the modified oviducts were unsuccessful in retrieving ipsilaterally ovulated ova, whereas the contralateral control oviducts apprehended an average of 72% of those available. Scanning electron microscopy showed the everted mucosa of the proximal ampulla to be less richly endowed with cilia than that of the normal fimbria. This ovum capture appeared to be prevented by deficiencies in both the ciliary mechanism of the neofimbria and the ability of the remaining ampulla to retain the egg. This evidence indicates that the proximal ampulla is unsuitable for reconstruction of a functional fallopian tube.