Objective The aim of this study was to evaluate serum thiol disulphide levels in patients with cutaneous leishmaniasis (CL) compared with a healthy control group and to investigate whether thiol/disulphide balance can be used as a new marker of oxidative stress in CL patients. Material and Methods This prospective study included 47 patients diagnosed with CL and 46 healthy individuals without any disease. Native thiol, disulphide and total thiol levels were used in plasma. Disulphide/total thiol, disulphide/native thiol and native thiol/total thiol levels were measured. Results Disulphide, native thiol disulphide and total thiol disulphide levels were significantly lower in CL patients compared with the control group. However, there was no statistically significant difference between CL patients and the control group in terms of disulphide/native thiol, disulphide/total thiol and native thiol/total thiol values. Conclusion Based on the data in our study, it can be said that the use of thiol/disulphide balance as a new oxidative stress marker in CL patients is not appropriate, but studies with a larger number of patients are needed.