The defect levels in Hg 1 - x Cd x Te p + n junction photodiodes were studied by using Deep Levels Transient Spectroscopy (DLTS). Two electron traps, E (0.06), and E (0.15) and two hole traps, H (0.075) and H(0.29), were obtained, respectively. Their concentrations are only a few percent of shallow levels. According to these characteristic parameters, the minority lifetime of the devices and the product of area times the dynamic resistance at zero bias are estimated.