The present subject matter relates generally to methods and apparatus for detecting cellular telephones using hearing assistance devices. In an embodiment, a hearing assistance device includes a processor and a radio frequency transceiver connected to the processor. A detection circuit is connected to the processor, the detection circuit including a band pass filter and where the detection circuit is adapted to monitor a radio frequency signal to detect a cellular telephone in proximity to the hearing assistance device based on the monitored signal. The hearing assistance device includes an acoustic input, a magnetic input, and a switch for selecting between the acoustic input and the magnetic input. The processor is adapted to actuate the switch from the acoustic input to the magnetic input when a cellular telephone is detected in proximity to the hearing assistance device.