The seminal vesicle of the guinea pig has been widely used as a model for the study of hormonal action on the male accessory sex organ, but there have been few attempts to quantify their cellular and tissue components. In the present study, the seminal vesicle of the guinea pig was described in the form of a morphometric model. Tissue samples were taken from the distal, middle and proximal regions of the gland and processed for light microscopy. Using a combination of a stereological point-counting technique and direct measurement, the relative volumes of different components (lumen, epithelium, lamina propria and fibromuscular layer) were determined. The relative numbers of the secretory cells and basal cells were also estimated. Following the estimation of the average size of the seminal vesicle, the relative volume of different components and the relative number of secretory cells were transformed into absolute data on a per average seminal vesicle basis. Similarly, the average sizes of the secretory cells and nuclei were also determined. The quantitative data generated from the present study will serve as a baseline for further studies of the seminal vesicle of the guinea pig. The techniques used in the present study are easy to apply, and data generated were objective and reproducible.