Ketosis is the metabolic disorder in dairy cattle in early stage of lactation (first 6-8 weeks). It occurs when energy requirement of the animal exceeds the energy intake which results in negative energy balance. This condition occurs due to low level of blood glucose. During glucose deficiency the body fat is mobilized and processed in liver to meet the energy requirements. When higher quantity of fat gets mobilized, these fatty acids are not properly metabolized in the body leading to increased level of ketone bodies (also called ketonemia) likes; acetone (also called acetonemia) acetoacetate acid and β-hydroxybutyrate (BHB) in the blood and accumulate in the liver. In blood, high level of ketone bodies & low blood sugar and presence of ketone bodies in urine are the characteristic features of ketosis. Reduced appetite in later stage of gestation or after calving or due to any disease conditions is one of the causes for ketosis. The condition is highly economically important as it results in reduced milk production during the peak lactation period and delayed conception leading to longer inter calving period.