Purpose: Leukocyte esterase is an enzyme secreted by neutrophils that can be found in the synovial fluid of Septic arthritis (SA) patients. In this study, we tried to investigate the sensitivity and specificity of leukocyte esterase in diagnosing septic arthritis. Methodology: Between 2019 and 2022, we obtained synovial fluid samples from forty-six patients suspected of having septic arthritis and fifty-eight healthy individuals and measured the WBCs, ESR, CRP, PMN, glucose, and protein of SF. We also used the leukocyte esterase dipstick test to investigate the level of LE in synovial fluid for one minute. Results: Based on clinical and paraclinical criteria, sixteen out of the forty-six patients were diagnosed with SA. When (++) was considered positive, the sensitivity and specificity of the LE dipstick test for the diagnosis of SA were 93.7% (95% CI: 81.8%-100%) and 60% (95% CI: 42.4%-77.5%, P=0.000), respectively. When both (+) and (++) were considered positive, they were 100% and 43.3% (95% CI: 25.6%-61.0% P=0.000), respectively. All the patients in the control group had negative cultures and LE test readings (specificity=100%). Conclusion: The LE dipstick test can be a valuable diagnostic tool in the initial diagnosis of SA since it is affordable, fast, and reliable.