A rete testis cannulation technique was used to compare the secretion of rete testis fluid with the production of spermatozoa and histological testicular parameters in Ile-de-France rams. Thirteen testes were cannulated and rete testis fluid variables were compared to histological variables of the same testis. The rate of flow of rete testis fluid was significantly (P less than or equal to 0.05%) correlated with testicular size, the area of the walls of the seminiferous tubules and the volume of the Leydig cells. These two latter factors accounted for 66% of the variation in the flow of rete testis fluid.