Functionally graded materials (FGM) have the mechanical property that varies at different sections of the material to suit the application. Functional grading could be arrived by varying the material constituent or the density of the pores in cellular structure, etc. Precise creation of pore size, shape, and relative density have a direct impact on energy absorption behaviour by Functionally Graded Cellular Structure (FGCS). The conventional production methods do not allow precise control over the shape size of the pores. Whereas the Additive Manufacturing (AM) techniques enable the production of complex shapes directly as it is designed without the need for any special tools. This paper investigates the effect of four different unidirectional pore shapes and relative density on energy absorption behaviour of FGCS under compressive load. The effect of four different pore shapes namely cylindrical, square, hexagon and triangular pore were considered for this study. These modelled cellular structures were fabricated using Fused Deposition Modelling technique. Compression test was conducted on linear gradient FGCS with four different pore shapes and it has been found that hexagonal pore FGCS has high energy absorption.