We have previously reported [J. Acoust. Soc. Am. 72, 1018–1020 (1982)] that a finite ultrasonic beam produces backward leaky‐Rayleigh waves from liquid‐solid interface. These backward propagating leaky‐Rayleigh waves are of much lower amplitudes than the forward one and observed with a single transducer in pulse‐echo mode. The objective of this paper is to report the observation of backward propagating leaky‐Lamb waves in plates immersed in water. [Forward propagating leaky‐Lamb waves were predicted and observed by Plona, Pitts, and Mayer, J. Acoust. Soc. Am. 59, 1324 (1976).] Several symmetrical and antisymmetrical Lamb modes were identified in brass and stainless‐steel plates by measuring the critical angle at which the back reflected signal (to the transmitter) is maximum. Backward propagating leaky‐Lamb waves are also observed with a second transducer on the transmitting side of the plate. The measured dispersion curves are in good agreement with theoretical predictions.