Sluggish diffusion in high entropy alloys (HEAs) has often been reported, but seldom proven by experimentation. The aim of the present study is to replicate some experimental results of Co, Cr, Fe and Ni family with an additional aluminum component to analyze diffusion rates as a function of temperature. To accomplish this goal two dissimilar and homogenized HEAs, a single phase Al0.7CoCrFeNi BCC alloy will be matched with another Al0.1CoCrFeNi FCC alloy in a diffusion couple. Two sets of samples will be annealed at 100°C, 200°C, 400°C, 800°C for periods of 4hr, 8hr, 16hr, 32hr and air cooled to room temperatures. The resulting samples will be analyzed for their final composition and structure. Secondly, a binary aluminum and nickel alloy with the same equal atomic aluminum composition will be tested in the same manner to determine the aluminum diffusion rate. The rate of aluminum diffusion in HEA will then be compared to that of the binary alloy to draw conclusions about the possibility of sluggish diffusion in multi-principle element alloys.