The micromechanical properties of a new series of sintered aromatic polyesters have been studied. Load-displacement curves obtained from a depth-sensing indentation instrument were used to evaluate the viscoelastic-plastic properties of these aromatic polyesters. The depths investigated lay within the micrometre scale. Hardness values derived from this technique have been compared with those obtained using a microindentation tester. The influence of particle morphology and unit cell symmetry on the mechanical properties of these materials was also investigated. The possible variation of hardness with the sintering pressure applied to the sample during preparation has been examined. The viscoelastoplastic properties of these new aromatic polyesters are discussed in the light of those previously reported for related aromatic homopolymers.