Noise and transport characteristics of CdTe gamma - and X-ray detectors have been carried out to determine the 1/f noise sources and their correlation with charge carriers mobility. The noise spectral density was measured by standard set-up. The noise of low ohmic samples has 1/f noise spectral density which increases with the square of voltage. The high ohmic samples show 1/f type noise in low frequency range. This flicker noise leads to degradation in the homogeneity of the contact. The excess of noise changes as 1/fa , 1 a 2 at 10Hz, and it is due to the multitrapping of the CdTe. Thiscontributes to the loss in charge collection efficiency.