The ability to freeze boar semen provides several advantages including improved biosecurity, reduced disease transfer, genetic banking, and more precise semen delivery into the sow to optimize fertility. Membrane Protective Technologies Inc. (MPTI) has developed a product, GameteGuard®, that protects bull sperm during freezing and thawing, ultimately improving pregnancy per AI in dairy cows [1]. The purpose of this study was to validate the benefits of GameteGuard® in boar semen cryopreservation. A lactose- 22%-egg yolk extender served as the control (CT) cryopreservation extender in comparison with GameteGuard® added to lactose-22%-egg yolk extender at two concentrations (7% = GG7 or 9% = GG9). Two replicate ejaculates from 10 commercial Duroc boars were collected using the double-gloved technique. Ejaculates were diluted 1:1 in 37 °C extender (AndroStar®Plus; Minitube, USA) and cooled to 17 °C before transport back to MPTI. Motility was assessed by CASA, then ejaculates were extended to a final concentration of 40x106 sperm/ml by drop-wise addition of Part B (containing 2% glycerol) after samples equilibrated to 4 °C. Straws (0.5 ml) were filled and frozen over liquid nitrogen vapor. Thawing of straws was performed in duplicate (2 straws/treatment/replicate) and analyzed for motility (CASA IVOS IITM, Hamilton-Thorne, Beverly, MA, USA), membrane permeability (SYBR 14, Propidium Iodide; ThermoFisher, USA) and acrosome integrity (lectin PNA conjugated-Alexa Fluor® 647; ThermoFisher, USA) immediately post-thaw (0 h) and after 3 h incubation at 37 °C. A multiple comparison ANOVA was performed using a Tukey model analysis to determine treatment differences (p<0.05). Motility of sperm for both GameteGuard® treatments was significantly better (a:b p<0.05) than the control at 0 h and after 3 h incubation (0 h:23±0.9a, 32.8±1.1b, 33.2±2.5b, and 3 h: 0.7±0.2a, 29.6±1.9b, 26.4±2.5b for CT, GG7 and GG9, respectively). The proportion of sperm having intact membranes with intact acrosomes was not different from the control at 0 h but improveed (a:b p<0.05) for both treatments over the control after 3 h incubation (0 h: 58.1±1.7a, 61.6±0.9a, 59.3±2.4a, and 3 h: 43.2±1.7a, 52.7±1b, 51.1±2.1b for CT, GG7 and GG9, respectively). When boars were separated on the basis of poor and good freezability, GameteGuard® had the highest effect on poor freezing boars (<35% motile post-thaw) as illustrated by the mean delta between CT and GG7 membrane intact sperm with intact acrosomes (16.2a vs. 2.8b%, respectively, a:b P<0.05). This improvement in poor freezing boars demonstrates GameteGuard®’s capacity to improve post-thaw sperm health even among boars with an unknown freezing status. Taken together, there is sufficient evidence to conclude that the inclusion of GameteGuard® in freezing extenders improves the post-thaw quality if boar sperm and warrants further work in extender optimization.