Combining the approaches of functionals associated with h−concave functions and fixed point techniques, we study the existence and uniqueness of a solution for a class of nonlinear integral equation: x(t) = 1 (t) − 2 (t) + µ t 0 V 1 (t, s)h 1 (s, x(s)) ds + Λ T 0 V 2 (t, s)h 2 (s, x(s))ds, where C([0, T], R) denotes the space of all continuous functions on [0, T] equipped with the uniform metric and t ∈ [0, T], µ, Λ are real numbers, 1 , 2 ∈ C([0, T], R) and V 1 (t, s), V 2 (t, s), h 1 (t, s), h 2 (t, s) are continuous real-valued functions in [0, T] × R.