The naturally dead broiler chicks from 10 different private farms in Faizabad and Sultanpur districts of Eastern Uttar Pradesh, India was collected for one year (May, 2017 to April, 2018) to record the mortality rate of chicks at the brooding stage in different disease conditions and to identify the causal agents involved in chick mortality along with the gross pathological changes. Salmonellosis, Colibacillosis, Aspergillosis, Mycoplasma Colibacillosis Complex and the gout were the diseases diagnosed on the basis of history, clinical signs, gross pathological lesions in the dead birds. The highest broiler chick proportionate mortality in the present investigation was recorded 68.13% due to Aspergillosis. This was followed by Colibacillosis (61.33%), Mycoplasma-colibacillosis complex (60.00%), Salmonellosis (56.83%), Gout (48.97%) and Yolk sac infection (46.67%).