This paper studies the problem of uniqueness of entire functions concerning four small functions and shows that if two entire functions f and g satisfy \bar{E}(aj, k, f)=\bar{E}(aj, k, g) for j=1, 2, 3, 4, where aj are four distinct small functions with respect to f and g, and k is a positive integer or ∞ with k≥8, then f≡g.
