Andraszek, K. and Smalec, E. 2011. The use of silver nitrate for the identification of spermatozoon structure in selected mammals. Can. J. Anim. Sci. 91: 239-246. The spermatozoon is one of the most diversified cell types, and the chromatin of the haploid spermatozoon genome is essentially different from that of the somatic cell as regards its chemical composition, structure and function. Although the structure of spermatozoon chromatin has crucial importance for fertilization and embryo development, standard staining techniques are still predominantly used for identifying semen quality and the assessment of spermatozoa is most often limited to detecting irregularities in their morphological structure. The aim of the present research was to evaluate the usefulness of silver nitrate staining for assessing spermatozoon morphology and identifying spermatozoon structure. Spermatozoa isolated from testes and semen were examined. Silver nitrate staining made it possible to identify many significant details of the morphological structure of the spermatozoon and could be successfully employed in sperm morphology assessments.