The transverse dimensions of pulp fibres influence strongly their response to the papermaking process, and most end-use properties of products. However, fibre transverse dimensions are difficult to measure. Confocal microscopy combined with image analysis has been used for rapid and accurate measurement of fibre wall cross-sectional area,perimeter, and thickness. Results on kraft pulp fibres obtained from a variety of wood species are presented. They demonstrate how fibre transverse dimensions are distributed within a species, and can be described analytically. Comparison between different species shows that species with coarse or thick-walled fibres are likely to be more heterogeneous. Implications for pulp quality and fibre selection for end-use requirements are discussed.