Abstract: A fistulary catheter for creating a sutureless mucosa-to-mucosa anastomosis. The catheter includes a rigid guide portion having a penetrating point and a fenestrated portion which has at least one fenestration communicating with a hollow interior and terminating in an opening which has an everted rim. The everted rim is desirably provided with a corrugated margin to grip the mucosa without compromising the blood supply. The guide portion may be hook shaped to guide the direction of the catheter or a metal probe may be used to guide a straight catheter. The guide portion may be flattened to minimize leakage around the guide portion. The fenestrated portion of the catheter may be straight or may be provided with varying degrees of tapering. The taper acts to hold the mucosa in place during the formation of the anastomosis. In an alternative embodiment, the fenestrated portion is straight without any taper and is used with spacers with differing diameters.