A method is developed for the conceptual design of the root airfoil of aft-swept wings, based on wing planform parameters and a baseline airfoil in the outboard wing. The aim of the design is to reduce form drag at the root by creating straight upper-surface isobars. The analysis of the pressure distribution over the root airfoil is based on two analytical methods: one for estimating the root e ect due to thickness and one for estimating the root e ect due to lift. These methods are combined with a vortex lattice method and a two-dimensional panel method to be able to estimate the pressure distribution over the root airfoil. This method is coupled with an optimization algorithm to allow for the design of the root airfoil using a CST parametrization. Results show that the designed airfoils have the expected characteristics of a typical swept-wing root airfoil in terms of camber, position of maximum thickness and incidence angle. However, further refinements to the method are required to predict the increase in thickness-to-chord ratio.@en