In this paper we study optimal control problems governed by fractional stochastic partial neutral functional integro-differential equations with infinite delay in Hilbert spaces. We prove an existence result of mild solutions by using the fractional calculus, stochastic analysis theory, and fixed point theorems with the properties of analytic α-resolvent operators. Next, we derive the existence conditions of optimal pairs of these systems. Finally an example of a nonlinear fractional stochastic parabolic optimal control system is worked out in detail. c ⃝2015 All rights reserved.Keywords: Fractional stochastic partial neutral functional integro-differential equations, optimal controls, infinite delay, analytic α-resolvent operator, fixed point theorem.