The field experiment involving red clover (Trifolium pratense L.) was carried out in 2003-2004 by means of randomized blocks in four replications on 20 m2 area plots. Two factors were studied in the experiment: 1. Clover cultivars (Dajana cv. – 2n and Bona cv. – 4n); 2. Pre-sowing seed stimulation with laser radiation with surface power density of divergent beam at the plane of free falling: R0 (with no radiation) and R3 and R6 mW cm-2, applied 1, 3 and 5 times. Shoot density per 1 m2, mean dry matter of a single shoot, as well as annual yields of green and dry matter were evaluated in full performance years. Radiation rates, cuts and cultivars significantly differentiated the clover shoot density per 1 m2. The best results were achieved on object R6x5 for Dajana cv. from the first cut. Average weight of a single shoot significantly decreased in all irradiated objects as compared to the control. The highest yields of green and dry matter were recorded in object R3x5; they significantly exceeded the values for control variants (by 11.5% and 12.2%, respectively). Diploid Dajana clover produced dry matter yield 27.6% higher than that of tetraploid Bona cv.