Tuberculosis, paratuberculosis and brucellosis are most important diseases affecting livestock and causing severe socioeconomic losses in India. The present study is aimed to determine the prevalence of brucellosis, tuberculosis in cattle, buffaloes, goats and sheep in organized livestock farms of Tamil Nadu, India. Our screening results showed that brucellosis was found 3.13 % positivity in cattle and buffaloes and 100% negativity in sheep and goats. Tuberculosis was found 0.11%, 8.1%and 0.16% positivity in cattle and buffaloes, horses, sheep and goat, respectively. In case of Paratuberculosis, 1.76 % and 2.89% and positivity were recorded in cattle, buffaloes and sheep and goat, respectively in organized livestock farms of Tamil Nadu, India. Since brucellosis, tuberculosis and paratuberculosis are considered under emerging and remerging disease list so continuous periodical screening of livestock needed to prevent spread of those infections and implementation of vaccination policy in high prevalence area.