The diffraction of a Gaussian ultrasonic beam in absorbing fluids has been shown to produce a Gaussian field distribution in the fundamental component [J. Acoust. Soc. Am. Suppl. 176, S23 (1984)]. Now we have derived an analytical expression for the second harmonic and find that it also is a Gaussian function in the quasilinear approximation. Our expressions for the second harmonic also are free of the nearfield oscillations characteristic of the radiation from a piston transducer [cf. S. I. Aanonsen, T. Barkve, J. N. Tjøtta, and S. Tjøtta, J. Acoust. Soc. Am.75, 749 (1984)]. Calculated results are compared with measurements taken with the Gaussian transducer described previously. Reasonable agreement between theory and experiment are found for both the fundamental and the second harmonic of an initially sinusoidal Gaussian ultrasonic beam in water at 2 MHz. [Research supported in part by the Office of Naval Research.]