The studies on the microhardness have been calculated the hexagonal close packed metals rhenium (Re), osmium (Os) and thallium (Tl). In this paper, the Vickers’s pyramidal indenter and the true hardness values has been evaluated. Debye temperatures of hexagonal close packed (HCP) of these three metals have been calculated by using X- ray diffraction intensities pattern with Philips 3020 powder diffractometer fixed with a proportional counter using filtered CuKα radiation; all the values have been evaluated at room temperature In this present work the calculated Debye temperature values θH 338 K, 426 K and 74 for Re, Os and Tl respectively. The calculated Debye temperatures of these hcp metals have been estimated from the hardness H values 135, 400, 27 kg/mm2 and are compared with those obtained from Debye temperature of specific heats (θD), Debye temperature of elastic constants (θE) and Debye temperature of X-ray intensity measurements (θM).