This study was objectively carried out to estimate population of red-headed vulture; documentation of its diurnal behavior, issues related to declining its number. Anbu Khairini, Tanahu Nepal was selected as study site. Data were collected applying transects walk technique maintaining 150m width on both sides of road during December, February and March. The binocular was used to observe the diurnal behavior of the vulture and camera was used to capture their photographs. Scan sampling method was applied to collect behavior data systematically during day time for twelve hours. Collected data were analyzed using descriptive analysis and non parametric Chi-square test. There were two adults and one sub-adult Sarcogyps calvus at Anbu Khaireni area. Red-headed vulture spends its time about 44.45, 42.86, 5.87, 3.21, 1.3, 1.1 and 1.15% for resting, flying, eating, scratching, sunning, disturbing and fighting respectively. Generally, the red-headed vulture was found resting on the branch of Bombax cieba and Lagerstoemia parviflora. Chi-square test showed that the population of the red-headed vulture has been declining significantly. This decline may be due to lack of carcasses since it was banning the dumping animal skeleton and carcass at this site. This study will contribute to conserve redheaded vulture in Nepal.