Ultrastructural studies on biopsy tissue from the right testis of a 39‐year old patient with varicocele revealed 2.5–5 μm thick invaginations of the lamina propria towards the lumen of the seminiferous tubules. These invaginations were of various lengths. The presence of invaginations was confirmed through examination of serial semi‐thin sections. In some seminiferous tubules two neighbouring deep invaginations were joined together thus completely encircling and thereby separating the basal compartment, and in some cases even the adluminal compartment, of the seminiferous tubule. The invaginations were surrounded continuously by the basement membrane and contained collagen fibres, cell processes of myoid cells and in some cases also their