Electronic Journal of Differential Equations, Vol. 2007(2007), No. 52, pp. 1-10. Title: Existence of $\psi$-bounded solutions for nonhomogeneous linear differential equations Author: Pham Ngoc Boi (Vinh Univ., Vinh City, Vietnam) Abstract: In this article we present a necessary and sufficient condition for the existence of $\psi$-bounded solution on $\mathbb{R}$ of the nonhomogeneous linear differential equation $x'=A(t)x+f(t)$. We associate that with the condition of the concept $\psi$-dichotomy on $\mathbb{R}$ of the homogeneous linear differential equation $x'=A(t)x$. Submitted January 26, 2007. Published April 5, 2007. Math Subject Classifications: 34A12, 34C11, 34D05. Key Words: $\psi$-bounded solution; $\psi$-integrable; $\psi$-integrally bounded; $\psi$-exponential dichotomy.