The ultrastructural examination of the testicular interstitial tissue of Egyptian dromedary camel was performed to observe the seasonal changes. The activity of the interstitial tissue cells increased largely in spring. This was indicated by the large number of mature Leydig cells and two to three layers of myofibroblasts around the basal laminae of the seminiferous tubules with large blood vessels in the interstitial tissue. The testicular activity was moderate in winter as indicated by the lower number of immature Leydig cells. The lowest activity was in summer when Leydig cells became inactive with pyknotic nuclei. The cells of interstitial tissue lost their junctions with each other leaving a large intercellular spaces and myofibroblasts transformed to fibrocytes. The testicular activity began again to increase in autumn. The testicular activity of camel, however, did not stopped in any season of the year, because even in non-breeding seasons a part of the interstitial tissue of the testis was working and active.

Key words: Camel, Interstitial tissue, Leydig cells, Myofibroblasts, Seasons, Testis