Summary: For a linear singularly perturbed system of functional differential equations with small time delays we find a change of variables that decomposes this system into a purely-slow system of ordinary differential equations and a purely-fast functional equation. This decomposition is a generalization of Chang’s decoupling transformation of singularly perturbed systems in the time-delay case. It is obtained by virtue of invariant manifolds and it can be found approximately in the form of asymptotic expansion. Using this transformation, we get reduced-order approximate models, stability and stabilizability criteria. This transformation can be further used in different control problems.