Abstract: A knit sock useful for patients susceptible to foot problems resulting from diabetes or other conditions includes a leg section and a foot section. The leg section has sufficient expandability to be drawn over and cover at least a portion of a leg of a wearer. The foot section includes a heel section, a toe section, a sole section, and an instep section. The instep includes a ventilation panel and a flex zone, each having a different stitch construction. The ventilation panel allows air to pass through the sock and the flex zone prevents bunching or wrinkling of the material against the skin of the foot.