An arteriovenous dialysis access graft configured to be implanted in a subject, comprising: at least one flexible conduit having first and second end portions (12, 22), wherein the first end portion is configured to connect to an artery of the subject and the second end portion is configured to connect to a vein of the subject such that blood flows through the at least one conduit from the first end portion to the second end portion; and at least one cannulation chamber (30, 40) positioned between the first end portion and the second end portion of the at least one conduit, the chamber comprising: an elongated housing (30h, 40h) having an inlet (32, 42) at a first end thereof and an outlet (34, 44) at a second, opposed end thereof, a posterior wall, a pair of sidewalls, and an open anterior portion defining a cannulation port (30p, 40p), wherein the cannulation port (30p, 40p) has a length that spans at least a major portion of a length of the housing (30h, 40h); a self-sealing material extending across the cannulation port (30p, 40p); and a longitudinal passageway (36, 46) defined by the housing (30h, 40h) and the self-sealing material that extends from the inlet (32, 42) to the outlet (34, 44) of the housing (30h, 450h); characterised in that the posterior wall and the sidewalls of the housing (30h, 40h) of the at least one chamber (30, 40) are formed of a substantially rigid material such that, when a dialysis needle is inserted through the self-sealing material and the cannulation port (30p, 40p), the needle is inhibited or prevented from extending through the posterior or the side walls of the housing (30h, 40h). at least one flexible conduit having first and second end portions (12, 22), wherein the first end portion is configured to connect to an artery of the subject and the second end portion is configured to connect to a vein of the subject such that blood flows through the at least one conduit from the first end portion to the second end portion; and at least one cannulation chamber (30, 40) positioned between the first end portion and the second end portion of the at least one conduit, the chamber comprising: an elongated housing (30h, 40h) having an inlet (32, 42) at a first end thereof and an outlet (34, 44) at a second, opposed end thereof, a posterior wall, a pair of sidewalls, and an open anterior portion defining a cannulation port (30p, 40p), wherein the cannulation port (30p, 40p) has a length that spans at least a major portion of a length of the housing (30h, 40h); a self-sealing material extending across the cannulation port (30p, 40p); and a longitudinal passageway (36, 46) defined by the housing (30h, 40h) and the self-sealing material that extends from the inlet (32, 42) to the outlet (34, 44) of the housing (30h, 450h); an elongated housing (30h, 40h) having an inlet (32, 42) at a first end thereof and an outlet (34, 44) at a second, opposed end thereof, a posterior wall, a pair of sidewalls, and an open anterior portion defining a cannulation port (30p, 40p), wherein the cannulation port (30p, 40p) has a length that spans at least a major portion of a length of the housing (30h, 40h); a self-sealing material extending across the cannulation port (30p, 40p); and a longitudinal passageway (36, 46) defined by the housing (30h, 40h) and the self-sealing material that extends from the inlet (32, 42) to the outlet (34, 44) of the housing (30h, 450h); characterised in that the posterior wall and the sidewalls of the housing (30h, 40h) of the at least one chamber (30, 40) are formed of a substantially rigid material such that, when a dialysis needle is inserted through the self-sealing material and the cannulation port (30p, 40p), the needle is inhibited or prevented from extending through the posterior or the side walls of the housing (30h, 40h).