We analyzed microRNA (miR)-142-3p expression in leucocytes of the peripheral blood and urinary sediment cell samples obtained from kidney transplant recipients who developed graft dysfunction. Forty-one kidney transplant recipients with kidney graft dysfunction and 8 stable patients were included in the study. The groups were divided according to histological analysis into acute rejection group (n=23), acute tubular necrosis group (n=18) and stable patients group used as a control for gene expression (n=8). Percutaneous biopsies were performed and peripheral blood samples and urine samples were obtained. miR-142-3p was analyzed by real-time polymerase chain reaction. The group of patients with acute tubular necrosis presented significantly higher expressions in peripheral blood (P<0.05) and urine (P<0.001) compared to the stable patients group. Also, in the peripheral blood, miR-142-3p expression was significantly higher in the acute tubular necrosis group compared to the acute rejection group (P<0.05). Urine samples of the acute rejection group presented higher expression compared to the stable patients group (P<0.001) but the difference between acute tubular necrosis and acute rejection groups was not significant in the urinary analyzes (P=0.079). miR-142-3p expression has a distinct pattern of expression in the setting of post-operative acute tubular necrosis after kidney transplantation and may potentially be used as a non-invasive biomarker for renal graft dysfunction.