Flower buds on potted plants of 17 black currant cvs were frosted to -3.3, -4.5 or -5.2 deg C at the grape, first flower or full flower stage. In all cvs frost damage was greatest in plants at full flower at -5.2 deg (3-9% flower bud survival) and least in buds at the grape stage at -3.3 deg (82-86% survival). Ben More, Ojebyn, SCRI 238/36/12 and 238/34/31 (related to Ben More) tolerated -4.5 deg until after the first flower stage while Baldwin and Magnus were susceptible at the grape stage. Seabrooks Black, Greens Black and Ben Lomond and its relatives were intermediate at -4.5 deg . The growth stage at which plants were frosted did not affect fruit size and mean fruit weights were 1.2, 1.29, 1.29 and 1.33 g for plants not frosted and frosted to -3.2, -4.5 and -5.2 deg , respectively.