A non‐contact laser‐ultrasonic technique is applied to the nondestructive measurement of the stiffness properties of cylindrical rods. Acoustic waves generated in a cylinder by a laser line source under thermoelastic regime are identified by the comparison between experiment and theory. Two stiffness coefficientsc11andc12are determined by measuring the arrival time of the reflected longitudinal wave (LL) and that of the head wave (HW). The effects of laser beamwidth and time duration on the measurement are found by numerical simulations. For such an application, a radius of 0.3 mm appears as a minimum limit for the sample size using a laser source of 0.1 mm beamwidth and 20 ns time duration. Stiffness coefficients of three aluminum rods are experimentally measured with good accuracy. © 2004 American Institute of Physics