The extremely complex structural organization of the mammalian testis creates particular difficulties for studying its organization, function and regulation. Spermatogenesis that tak incorporates juxtacrine, paracrine and endocrine factor information, and is conditioned by the successive activation and/or repression of thousands of genes and proteins, including numerous testis-specific isoforms. it has been yet established that germ cells modulate somatic Sertoli cell function via diffusible proteins. However, the impossibility to maintain germ cells in vitro makes it difficult to study their secretome. Interestingly, within the seminiferous tubules, germ cells and Sertoli cells are surrounded by the testicular fluid, which probably contains factors involved in the germ cell-somatic cell crosstalk. An innovative approach combining testicular fluid collection by microsurgery, fluid prefractionation, shotgun mass spectrometry and «combinatorial omics» was used to decipher and mine the rat and ram testicular fluids. Over 1400 non redundant proteins were identified and their presence in testicular fluids was further correlated with the transcriptome of isolated testicular cells so as to confirm their cellular origin. Secreted proteins were identified and scored using the Secreted Protein Database (SPD). We demonstrate here that a subset of proteins is actively secreted into the test icular fluid by germ cells. Potential known partners of these germ cell-secreted proteins were proposed using protein network data available via certified public repositories and those known to be expressed on Sertoli cells plasma membranes were selected for further studies. Coexpression of potential germ cell-Sertoli cell protein partners was validated using immunohistochemistry on rat testis sections. Our results provide new insights into the germ ceii -Sertoli cell crosstalk by identifying novel interacting protein partners. We also demonstrate that «combinatorial omics» is a powerful approach to characterize the testicular germ cell secretome that was so far technically inaccessible.