A read-only memory (ROM) includes ROM cells and a bias control circuit for biasing the ROM cells. Each ROM cell includes a set of transistors. The bias control circuit is connected to body terminals of the transistors of each ROM cell to provide a bias voltage. The bias voltage, which is temperature-dependent, is generated based on junction leakages at the body terminals of the transistors. The bias control circuit controls threshold voltages of the transistors using the bias voltage. The use of a temperature-dependent bias voltage to bias the body terminals of the transistors allows for a relatively constant read margin for each ROM cell.