AbstractSeveral recent studies suggest a diagnostic and a possible prognostic role for silver stained nucleolar organizer region (AgNOR) determination in the assessment of human neoplasia. Technical pitfalls, especially silver grain precipitate, may hamper accurate counting of AgNORs. We have identified pH as a main factor causing silver precipitation and overstaining. An improved silver staining method, which raises the pH to 3.0, optimizes visualization by eliminating silver precipitation and improving contrast between AgNORs and surrounding tissue components. (The J Histotechnol14:187, 1991)