A header-less implantable medical device, system and method are provided. The device includes an electronics module including circuitry, a battery, a receptacle assembly having an interior chamber and a receptable inlet configured to receive a lead connector assembly. A device housing has a case body that includes side walls and a peripheral edge that defines a single common chamber. The electronics module, battery and receptacle assembly are provided within the single common chamber. A connector opening is provided in the case body and joined to the receptacle inlet to form a passage through the case body into the interior chamber of the receptacle assembly.