Abstract: In a method of preserving sperm of domestic animals, especially for the purposes of artificial insemination, a quantity of the sperm, diluted if necessary with a diluting solution, is maintained in communication, through a dialytic membrane, with a quantity of Ringer's solution containing albumin or activated carbon, the whole being maintained at a constant temperature preferably of about 15.degree. C. An antibiotic may be added to the sperm to prevent bacterial growth.