The aim of this study was to investigate the effect of chlorogenic acid (ChA) in boar semen stored at 15°C. Twelve ejaculates were processed into insemination doses at different concentrations of ChA (0.0, 1.5, 3.0, 4.0 and 6.0 mg/ml) or vitamin E (200 μl/ml) as positive control. Semen was analysed after 0, 24 and 72 hr of storage. ChA improved (p < .05) sperm motility, acrosome integrity and mitochondrial activity in all periods of storage. Furthermore, after 24 hr of storage, ChA above 1.5 mg/ml supported the sperm viability until 120 min after reheating (p < .05). Both ChA and vitamin E were similarly efficient in increasing the antioxidant capacity of semen, reducing the malondialdehyde levels before and after 72 hr of storage (p < .05). However, with 72 hr of storage, ChA at 3.0 mg/ml improved the mitochondrial activity over vitamin E (p < .05). In conclusion, results suggest that the concentration of 3.2 mg/ml of ChA is the best for semen stored for up to 24 hr. However, for semen stored for a longer period, 6.0 mg/ml or more should be used.