© 2021 College of Physicians and Surgeons Pakistan. All rights reserved.Objective: To determine the relationship of oxidative stress status with follow-up parameters, metabolic control status, and treatment compliance evaluation in patients diagnosed within toxication type inherited metabolic disease (IMDs). Study Design: Descriptive, analytical study. Place and Duration of Study: Dr. Sami Ulus, Maternity and Child Health, Training and Research Hospital, Ankara, Turkey, between September 2019 and March 2020. Methodology: Sixty-seven patients, who were followed up with a diagnosis of IMDs in the pediatric metabolism outpatient clinic, and 41 healthy volunteers who applied to the social pediatrics outpatient clinic, were evaluated. Disulfide/native thiol, disulfide/total thiol, and native thiol/total thiol ratios of the patient and control group were calculated. P <0.05 (*) value was considered significant in statistical analysis. Results: The mean native thiol / total thiol ratio of the patient group was significantly lower when compared to the control group (92.0±3.3 vs 94.1±2.7, p=0.001). The median disulfide level [19.8 (11.6-25) vs 14(10.1-18.8), p=0.004], the mean disulfide / native thiol (4.5±2.0 vs 3.2±1.6, p<0.001) and the mean disulfide / total thiol ratios (4.0±1.7 vs 2.9±1.4, p=0.001) were higher in the patient group compared to the control group.The findings showed that oxidative stress status was increased during metabolic attacks. Poor metabolic control and non-compliance to treatment was found to be associated with increased oxidative stress. Oxidative stress parameters were found to be correlated with metabolic chemicals such as ammonia, leucine, and citrulline. There was no correlation between phenylalanine and lactate levels and oxidative stress parameters. Conclusion: Metabolic control status and compliance with treatment are related to oxidative stress level, showing thiol/disulfide balance in urea cycle defects, phenylketonuria, and galactosemia patients.