The study was conducted to determine the eﬀects of supplementing activated IGF-I (aIGF-I) in lactating diets on sow and piglet performance. Fifty nine crossbred female pigs (average parity 1.91 ± 0.30) were randomly assigned to two dietary treatments following randomized complete block design with parity as blocking factor. Treatments were basal lactation diets added with 0 (n=30) or 3 kg/ ton aIGF-I (n=29). The feeding trial started from day 100 of gestation until weaning. Dietary supplementation of aIGF-I reduced backfat loss of sows associated to reproduction (1.35 vs 3.87 mm, P<0.05). Piglets from sows fed diets with aIGF-I have higher body weight gain at 24 hours post-farrowing (0.12 vs 0.08 kg, P<0.05) and adjusted 30-day weaning weight (7.86 vs 7.16 kg, P<0.01); while preweaning mortality was reduced by 50.12% (4.08 vs 8.18%, P<0.05). Results demonstrated the potential of supplementing aIGF-I during late gestation and lactation in reducing backfat thickness loss at lactation of sows associated to reproduction and increasing growth and survivability of piglets.