The objective of this study was to investigate the influence of the addition of extenders after semen cryopreservation-thawing on boar sperm quality. To evaluate the effect of pentoxifylline and investigate optimum concentrations in extender freezing medium on motion characteristics, motility, viability and mitochondrial activity of spermatozoa at post thawing of cryopreservation. Semen were collected from five boars and frozen on the same day. Qualified semen samples (motility >80%) from each boar were subdivided into four groups, 0 (control), 5 mM (T1), 10 mM (T2) and 20 mM (T3) to evaluate the effects of pentoxifylline. Motility was assessed for % motile cell characteristics using computer-assisted semen analysis (CASA; SAIS SI-100, Medical supply, Korea). Viability was assessed using the LIVE/DEAD kit (Molecular Probes, USA) and mitochondrial activity was examined by MitoTracker (Invitrogen, USA). Frozen sperms were thawed in Beltsville Thawing Solution (BTS) then incubated at 38℃ for 30 minutes. The addition of 10 mM/L pentoxifylline to cryopreserved semen after thawing significantly increased progressive, total motility and mitochondrial activity compared to controls. Progressive motility, Linearity, Straightness ratio VSL/VAP were higher (P < 0.05) in group T2 compared to control group. Nevertheless, pentoxifylline concentration treatment did not affect the viability of the spermatozoa as the concentration increased. The data showed that pentoxifylline as an additive cryoprotectant was able to improve sperm motility and also quality in cryopreservation.