Utilizing a simplified equivalent circuit for an electroacoustic transducer with a single resonance, it is shown that the mean‐square thermally generated noise voltage for the entire frequency range is justkT kc2/C0, wherekis the Boltzman constant,Tis the Kelvin temperature,kcis the effective electromechanical coupling coefficient, andC0is the clamped capacitance. This voltage is generated by the mean total thermal energykTin the circuit, which results from the circuit's two degrees of freedom. From impedance measurements on a transducer with two pronounced resonances, it has been shown that this relationship, with some modifications, approximates the conditions existing in a transducer with multiple resonances. Expressions for the equivalent noise pressure of a transducer and applications to the measurement of low‐level signals with a resonant transducer are discussed.