Introduction: Most functional neuroimaging methods, including fMRI, rely on the hemodynamic response following neural activation. Consequently in order to correctly interpret the results of neuroimaging experiments both the functional and the structural neurovascular coupling must be well understood. The former includes the degree and density of cortical vascularization. Here we studied the layer and area specific vascular differences in areas V1, V2, V3, V4 and V5 in the macaque monkey. Methods: Formalin-fixed frozen sections of 4 animals (M. mulatta) were processed for double fluorescence immunohistochemistry. Sections were incubated with anti-collagen type IV and DAPI to stain for vessels and cell nuclei. The length density (mm/mm?) of vessels was taken as a measure for vascular density. Layer and area specific regions of interest were determined on the basis of the DAPI stain and if necesary with the help of consecutive Nissl and myelin stains. Results: The procedure yielded high quality vessel-specific images with excellent reproducibility within and between animals. In V1, the vascular density was highest in layer IVc-β (871.9 +/- 47.1 mm/mm?, mean +/- sd of 4 animals) and lowest in l