This study was performed to investigate the clinical findings, some hematological and biochemical findings, and sex and age status in feline immunodeficiency virus (FIV) seropositive cats. In 37 FIV-seropositive cats, different clinical symptoms were observed (group 1). However, seven of the FIV-seropositive cats showed no clinical symptoms (group 2). The control group was made up of 116 healthy cats. FIV infection was seen more in male cats (78.4%) than in female cats. 62% of the FIV-seropositive cats were over 5 years old. Group 1 of FIV-seropositive cats showed symptoms of stomatitis/gingivitis (21.6%), extreme weight loss (10.8%), chronic infection in the respiration ways (10.8%), anemia (13.5%), swollen lymph nodes (8.1%), tumors (5.4%), disease of eyes (5.4%), anorexia (13.5%), limping (8.1%), uremia (13.5%), diarrhea and vomit (5.4%), dermatitis (5.4%) and cardiomyopathy (5.4%). When the biochemical parameters of group 1 were compared with those of the control group, the enzyme activities of ALT and GLDH, and the concentrations of plasma bilirubin, total protein, urea and potassium were significantly increased (p<0.05). The concentrations of plasma total calcium were significantly decreased (p<0.01), and the plasma concentrations of natrium were lower than the reference range in 21.6% of the cats in group 1. The hematological parameters of group 1 were compared with those of the control group, and the thrombocyte count was found to be significantly decreased (p<0.01), and the leucocyte count significantly increased (p<0.01). However, all cats with leucocytosis showed lymphopenia, and 5.4 % of group 1 of FIV- seropositive cats had leucopenia. There were no significant differences in erythrocyte count and hematocrit value between group 1 and the control group. However, the erythrocte count and the hematocrit values were lower than the reference range in 13.5% of group 1 FIV-seropositive cats. The concentration of plasma total protein (p<0.01), and potassium (p<0.05) were significantly increased; however, the concentration of plasma calcium was significantly (p<0.01) lower in group 2 of FIV- seropositive cats compared with the control group. Thrombocytopenia (n=1, and significant decrease p<0.01) and leucopenia (n=2) were also seen in group 2 of FIV-seropositive cats.