A medical access device provides needleless access to patient fluid lines such as intravascular catheters. A retaining ring at the top end of the housing of the medical access device is molded around a septum that provides access for a tubular portion of a medical device such as a male luer taper of a syringe. Alternatively, the retaining ring may also be molded around the body or around both the body and the base of the housing. The molded retaining ring and septum are attached by mechanical attachment and/or chemical adhesion to minimize axial and rotational movement between the septum and the housing.