20 csases with IDDM (GroupA) and 10 healthy controls recently fertile (Group B) were selected to study the effect of IDDM on both the hypothalamic-pituitary-gonadal axis and the semen parameters under the electron microscope. Both patients and controls did hormonal assay (prolactin testosterone, FSH and LH), semen analysis under light and electron microscopy and GnRH test. There was a Significant difference between both groups with lower level of testerone, prolactin and FSH and higher LH in (Group A). This means that IDDm may affect the hormonal axis at different levels and that this effect may be, even partially a cause of the effect of IDDM on the semen under the electron microscope