Ketosis is an important metabolic disease of high milk-producing cows. There are significant changes in many metabolite and hormonal concentrations in metabolic diseases. This study was carried out to assess the concentrations calcium (Ca), selenium (Se), total antioxidant (TAOC), insulin, free triiodothyronine (fT(3)) and free thyroxine (fT(4)) in cows with subclinical and clinical ketosis. This study included 20 dairy cows within the first two months of lactation, aged between 4-8 years. Cows with beta-hydroxybutyrate acid (BHBA) concentrations 1.20 mmol/L were considered healthy, whereas 1.20 and 1.50 mmol/L were considered subclinical and 1.60-2.20 mmol/L were classified as clinically ketotic. Serum aspartate aminotransferase (AST), alanine aminotransferase (ALT), low density lipoprotein (LDH), glucose, Ca, plasma TAOC capacity and BHBA concentrations were performed spectrophotometrically. Serum insulin, free triiodothyronine and free thyroxine concentrations were measured using the chemi-luminescence method. Serum Se concentrations were measured using an Inductively Coupled Plasma-Mass Spectrometry (ICP-MS). In conclusion, significant changes were noted in decreased concentrations of TAOC, Ca, Se, fT(3), fT(4) and insulin in cows with subclinical and clinical ketosis. The study identified important parameters, changes in the levels of these parameters will be important in determining the treatment and prognosis of the disease. Their use may also help reduce the economic losses suffered by dairy farmers as a result of the disease.