The present study was designed to evaluate serum biochemical and haematological parameters and serum nitrate concentrations in cattle suffering from foot- and -mouth disease (FMD). For this purpose, 30 Swiss Brown cattle aged between 3 and 5 years were used. Twenty cattle showed characteristic clinical signs of FMD, whereas the remaining 10 were clinically healthy and used as controls. Peripheral blood samples were collected from both groups and used to establish total white blood cells (WBCs), red blood cells (RBCs), haemoglobin (Hb), and haematocrit (PCV), mean corpuscular volume (MCV), mean corpuscular haemoglobin concentration (MCHC) and mean corpuscular haemoglobin (MCH). Serum samples were also collected from these animals and used to establish the concentrations of total protein, albumin, urea nitrogen, creatinin, glucose, calcium, phosphorus, nitrate (NO3) and cholesterol and activity of alanine aminotransferase (ALT), aspartate aminotransferase (AST) and alkaline phosphatase (AP). There was a significant decrease in the total number of RBCs (P < 0.05) and a significant increase in MCV (P < 0.05) in cattle with FMD compared to the control group. There were no significant differences in the other haematological parameters evaluated. Serum glucose concentration was significantly higher (P < 0.001) in the FMD group than in the control group. Serum total protein (P < 0.05), calcium (P < 0.01), albumin (P < 0.001) and cholesterol (P < 0.01) levels were significantly low in the FMD group compared to those in the control group. However, there were no significant differences in the other biochemical parameters between the groups. The concentration of serum NO3 was significantly high in the FMD group, suggesting that Aphtovirus induces the production of nitric oxide in vivo.