A hearing aid having a battery door seal that substantially reduces or eliminates unwanted air flow from and into a battery compartment is provided. Eliminating unwanted air flow removes a potential source of acoustic feedback and provides significant improvement in frequency response of the hearing aid. The hearing aid includes a battery compartment with sidewalls that have a step joint formed between an opening in a faceplate to the battery compartment and a substantially flat portion of the sidewalls. The battery door has a lip that sets on the step joint when the battery door closes providing an air seal around a substantial portion of the battery compartment. A thin slit is provided between the faceplate and the battery door behind the end of the battery door, where the battery door is connected to the faceplate by a hinge to provide appropriate air flow for proper battery operation.