The intramammary administration of platelet concentrate is expected to treat subclinical mastitis and prevent disease recurrence effectively; therefore, it was aimed to evaluate its efficacy in terms of somatic cell count (SCC) and Milk Amyloid A (MAA) measurements. A total of 120 cow mammary lobes with subclinical mastitis were randomly assigned to one of the following three groups: Antibiotic Group (ABG, n=40), Platelet Concentrate Group (PCG, n=40) or Combined Group (CG, n=40). Platelet concentrates were prepared by the double centrifugation method from blood collected from donor cows. All groups received intramammary treatments for 3 days. Analysis of MAA using a commercially available ELISA method and measurement of SCC were performed from milk samples collected on days 0, 7, 14, and 21. Treatment success and absence of recurrence were found to be statistically significant for all three treatment protocols (P<0.001). It is concluded that intramammary platelet concentrate administration can be an effective alternative to intramammary antibiotic use for the treatment of subclinical mastitis.