Electronic Journal of Differential Equations, Vol. 2019 (2019), No. 63, pp. 1-14. Title: Approximate controllability of quasilinear functional differential equations Authors: Duranta Chutia (Tezpur Univ., Sonitpur, India) Rajib Haloi (Tezpur Univ., Sonitpur, India) Abstract: In this article, we study the approximate controllability for quasilinear differential equations with deviating arguments in a Hilbert space. We establish sufficient conditions for the existence of a mild solution. We also obtain sufficient conditions for the controllability of quasilinear equations. Further, we use it to establish the approximate controllability for quasilinear differential equations with deviating arguments. We discuss examples in which the analytical results are applied. Submitted July 30, 2018. Published May 08, 2019. Math Subject Classifications: 35K59, 35K90, 93B05, 93C25. Key Words: Quasilienar equations; approximate controllability; deviating arguments; Krasnoselskii's fixed point theorem.