Modeling of continuous and controlled nanocrystal synthesis in a microfluidic reactor is presented. The population balance model that describes the nanocrystal synthesis consists of a population balance equation and a set of species concentration equations. In order to incorporate the effects of both reaction and diffusion limited growth conditions, a kinetic model with size-dependent growth and nucleation rate expressions are considered. An efficient finite element scheme based on Strang splitting that handles size-dependent particle diffusion and non-uniform growth expressions in the high dimensional population balance equation is proposed to solve the model equations. After the validation of the numerical scheme, an array of parametric studies is performed to study the effects of the flow condition and the growth environment on the nanocrystal synthesis in the microfluidic reactor. The computational results are consistent with the experimental observations. (C) 2016 Elsevier Ltd. All rights reserved.