This paper is concerned with entropy solutions of scalar conservation laws of the form \(\partial_{t}u+\diver f=0\) in \(\mathbb{R}^d\times(0,\infty)\). The flux \(f=f(x,u)\) depends explicitly on the spatial variable \(x\). Using an extension of Kruzkov's method, we establish the \(L^1\)-contraction property of entropy solutions under minimal regularity assumptions on the flux.