The present invention provides stable pharmaceutical compositions, comprising a pharmaceutically effective amount of testosterone or a pharmaceutically acceptable ester thereof, a pharmaceutically acceptable oil vehicle, and a stabilizing amount of benzyl alcohol, for example, about 1% to 3% weight/volume of benzyl alcohol. The present invention also provides a process for stabilizing testosterone-containing pharmaceutical compositions by ageing them at a temperature of about 20° C. to about 60° C. for at least 48 hours, e.g., prior to secondary packing and labeling. These compositions were stable over the shelf life of the product, without exhibiting crystal formation, even upon storing at temperatures of about 2° C. to about 8° C. Other aspects of the invention relate to methods for making such pharmaceutical compositions, as well as methods of using such pharmaceutical compositions for hormone replacement therapy, e.g., in a male patient having a condition associated with symptoms of deficiency or absence of endogenous testosterone.