As composite materials are increasingly used in aircraft structures it is becoming equally important to be able to accurately measure the quality of these materials. Due to their non-homogenous composition, composite materials are prone to manufacturing defects, such as void content/porosity, delamination and matrix cracks. These parameters can act as failure initiation points and therefore their identification and characterisation is important in determining the quality of a manufactured composite structure. Conventional composite characterisation techniques, such as microscopy, matrix burn-off and matrix digestion have been proven to give results of limited accuracy and/or reliability. Microcomputed Tomography (micro-CT) however is a novel non-destructive and visual technique that can be used to produce three dimensional images of an objects internal structure. The aim of this study is to assess the accuracy and reliability of conventional and novel void characterisation techniques for composite materials in collaboration with the Defence Technology Agency (New Zealand). Archimedes Theoretical verse Actual Density, microscopy and micro-CT are compared with respect to their accuracy and reliability of analysing carbon fibre reinforced composite (CFRC) laminates. The Archimedes Theoretical verse Actual Density technique, which is non-destructive and non-visual, was found to be reliant on accurate material properties and mass fraction values of the two primary constituents, introducing large standard deviations into the results. Microscopy is a visual yet destructive technique, with Scanning Electron Microscopy (SEM) providing better contrast and quality than the conventional optical microscopy. SEM is able to image the complete specimen cross-section, allowing for two-dimensional void cross-sectional analysis of void size, shape and distribution. This technique however has an inherent section bias error that contributes to a generally large standard deviation. Micro-CT analysis on the other hand was found to have no inherent errors and is able to characterise the three-dimensional size, shape and distribution of voids in a CFRC. The accuracy of micro-CT was also verified by analysing artificial voids of a known size and shape disbursed in a CFRC laminate sample. ; Available to authenticated members of The University of Auckland.