Background: MMP-3 is a proteolytic enzyme of the matrix metalloproteinase family. Protein degradation which is their fundamental action regulates different activities of tumor cell such as their growth, differentiation, apoptosis, migration, invasion, angiogenesis as well as their resistance to the immune system. Aim: The aim of this study was to determine MMP-3 serum levels in patients with OSCC and investigate if they correlate with clinicopathological features. Method and materials: Using an ELISA kit, we assessed and compared the circulating levels of MMP-3 in blood serum of 45 oral squamous cell carcinoma patients with 45 healthy control samples. Results: The serum MMP-3 level in OSCC patients was significantly higher ($9.45{pm}4.6$ ng/ml) than healthy controls ($5.9{pm}3.6$ ng/ml, p<0.001), especially in females and in older patients. However, there was no apparent correlation in serum MMP-3 concentration with the clinico-pathological features such as tumor location, stage, tumor size, nodal status, distant metastasis, histological grade and smoking. Discussion: This result suggests that the measurement of serum MMP-3 concentration might be helpful to diagnose OSCC but not to predict prognosis.