Experimental results are presented from a study of changes in the ductile-to-brittle transition temperature of VVER-440 base and weld metals under cyclic irradiation and recovery. The transition temperatures were determined from the results of subsize V-notch impact specimens measuring 5 by 5 by 27.5 mm. Specimen irradiation was carried out in a commercial reactor at a temperature of 270°C in three irradiation and recovery cycles. Annealing of specimens was performed at 340, 420, and 460°C. The shift in the transition temperature of subsize specimen data in the first irradiation cycle was compared to the transition temperature shift determined from tests using standard Charpy specimens.