Abstract: An anastomosis system and methods for its use in end-to-side anastomoses are provided. The subject anastomosis system includes nesting, first and second structural means which are each tubular in structure and have a lip at at least one end. In performing an end-to-side anastomosis according to the subject invention, the subject anastomosis system is used to stably attach the graft vessel to the side of the host vessel in a manner that provides for fluid communication between the lumens of the graft and host vessels. Also provided are kits that include the subject systems. The subject anastomosis systems and methods find use in a variety of different anastomosis applications, including vascular anastomoses, and particular proximal anastomoses.