Spermatogenesis is a fundamental biological process that ensures gee transmission from one generation to another trough gametes. This process relies on a rare population of testicular cells, called spermatogonial stem cells (SSCs), that self-renew throughout adult male life and differentiate into mature gametes. Despite the longstanding research of SSCs, their biological properties remain largely unknown which is partly due to very limited availability of these cells. Here we show that cell adhesion protein E-cadherin is a highly specific surface marker of mouse SSCs, which can be successfully used for their enrichment.