There's really not a whole lot of difference. I'm looking at both of them right now (I have them both). Medium is a bit more pink and medium beige is a bit more brown. I use the two interchangeably and truly don't notice a difference on my skin. The only reason I have the medium beige is because when I got my very first kit (from the infomercial) it came with two shades (med and med/beige) so you could blend the two. When I bought a refill at the store, I just bought the medium. Really, I just put both on my hand and I see no color difference.