We study the stability properties of semi-wavefronts of the KPP-Fisher equation with infinite delay partial derivative/partial derivative t u(t, x) =partial derivative(2) /partial derivative x(2) u(t, x) +integral(+infinity)(0)u(t - s, x)d mu(1)(s)(1 -integral(+infinity)(0) u(t - s, x)d mu(2)(s)), t > 0, x is an element of R, where mu(1) and mu(2) are Borel measures. We show an interesting property about the non convergence in form when the delay is finite, unlike the classic convergence result to KPP-Fisher equation without delay. We also present a result about the stability of semiwavefronts to the Neutral KPP-Fisher equation.