Carbon nanocomposites have exciting potential but often display poor performance. The limitations are often attributed qualitatively to issues of distribution and dispersion within the matrix, factors that are sensitive to the processing technique and conditions employed. Unfortunately, there are relatively few methodologies available for the quantification of inhomogeneous carbon nanotube distributions. Understanding the relationships between microstructure and properties is crucial to developing the next generation of carbon nanocomposites; consequently, there is a growing need for new, quantitative approaches to characterise the distribution of fillers in nanocomposite materials. Here, Raman spectroscopy is used to quantify the concentration of multi-walled carbon nanotubes (MWCNT) in compression moulded epoxy composites across differing concentration regimes. While Raman is a powerful tool, scans of statistically relevant areas can be time consuming to obtain. Since MWCNT are strong optical absorbers, optical microscopy in transmission mode can also be used to quantify the density of MWCNT fillers and visualize the MWCNT concentration across the composite. Through correlating the intensity of the Raman G-band to the transmittance intensity, rapid and quantitative analysis of MWCNT distributions over large areas of the composite (>100 µm x 100 µm) can be achieved. This powerful tool enables quantitative mapping of the concentration of MWCNT, thus allowing quick verification of manufacturing processes with applications for fundamental development and quality assurance in a commercial context.