The invention provides an article of manufacture comprising a substantially non-immunogenic heart valve xenograft for implantation into humans. The invention further provides methods for preparing a heart valve xenograft by removing at least a portion of a soft tissue from a non-human animal to provide a xenograft; washing the xenograft in saline and alcohol; subjecting the xenograft to cellular disruption treatment; treating the xenograft with crosslinking agents, and digesting the xenograft with a proteoglycan-depleting factor and/or glycosidase. The invention also provides an article of manufacture produced by the above-identified method of the invention. The invention further provides a heart valve xenograft for implantation into a human including a portion of a heart valve from a non-human animal, wherein the portion has extracellular components and substantially only dead cells. The extracellular components have reduced proteoglycan molecules. Each of the xenografts of the invention are substantially non-immunogenic and have substantially the same mechanical properties as a corresponding native heart valve.