Abstract Electrical properties have gained interest in biofuels applications due to advances in radio frequency and microwave processing and characterization of biodiesel. In those applications, sensors play a key role since the accurate measurement of electrical properties is needed. This work presents the design, construction and characterization of a broadband (1 kHz to 100 MHz) permittivity sensor for biodiesel and blends. The sensor was characterized in the temperature range from 293 K to 343 K in the full intended frequency range. The sensor is apt for industrial use, inexpensive, and easy to build and it has very low electrical losses. For low permittivity substances the measurement uncertainty is below 1%, up to 100 MHz.