Hydraulic fracturing is not a new technology and has become an essential part of petroleum industry to produce oil and gas. The goal of hydraulic fracturing is to create a highly conductive fracture system that will allow flow of fluid and/or gases through the formation to production well. A proppant is a solid material, typically sand, treated sand or man-made ceramic materials, designed to keep an induced hydraulic fracture open. Many proppants and mesh sizes are available for the design of a fracture stimulation treatment. Proppant types and sizes are effected on the fracture conductivity. This paper describes the factors which are critical to proper proppant selection and ultimately, proppant performance. Proppant fines, Proppant pack cyclic stress, Effective Vs Reference conductivity, Proppant flowback, Proppant pack rearrangement, Proppant embedment and Downhole proppant scaling are explained in relation to proppant selection.