A differential diagnosis of testicular torsion and epididymitis has serious importance for testicular health. In emergency conditions, if testicular torsion goes unnoticed and epididymo-orchitis is diagnosed, organ loss may occur. This study aimed to evaluate the usefulness of haematologic parameters for the diagnosis of both testicular torsion and epididymo-orchitis and for differential diagnosis of these two diseases. Patients were divided into three groups as those undergoing surgery for testicular torsion, those receiving medical treatment for epididymitis and a healthy control group. All patients had complete blood counts taken with determinations of mean platelet volume (MPV), platelet/lymphocyte ratio (PLR), neutrophil/lymphocyte ratio (NLR) and leucocyte counts. These were then compared between groups. Leucocyte, MPV and NLR values were higher in both the epididymitis and torsion groups compared to the controls (p < .001). Platelet counts and PLR were significantly higher in the epididymitis group compared to the other two groups (p < .001). Leucocyte, MPV and NLR values may be used in the diagnosis of epididymitis and testicular torsion. Platelet counts and PLR appear to be useful in differentiating epididymitis from testicular torsion. However, there is a need for prospective studies with larger numbers of patients.