If low absolute pressure is first applied to and then released from seeds ofPinus sylvestrisL. lying in water, the seeds with mechanical damage, i.e. with seed coat cracked, with part of seed coat missing or with part of seed coat and gametophyte missing, quickly lose their buoyancy and sink and can thus be separated from the floating undamaged seeds (PREVAC method). The most crucial of the tested physical properties was the level of pressure. The time of treatment (1–20 min) was of less importance, and the water temperature (5–40°C) was unimportant. Treatment at approximately 97 kPa below atmospheric pressure (3–5 kPa absolute pressure) for 1 up to 20 min resulted in removal of almost all mechanically damaged seeds in the four studied seed lots (containing up to 26% damaged seeds). In total, less than5%undamaged seeds of the whole seed lots were removed. The germination percentage of the fractions remaining after separation increased with increasing number of damaged seeds in the seed lots and vice versa for the removed fractions.