Background: Eating disorders (ED) can cause significant disturbance of the menstrual cycle and impaired female fertility. The comorbidity of ED in type 1 diabetes mellitus (T1DM) leads to poorer glycemic control and subsequently more complications. Nesfatin-1 is a neuropeptide that performs an important role in controlling food intake, gastrointestinal motility, glucose homeostasis, and reproductive functions. This study aimed at exploring the serum nesfatin-1 levels in female patients with diabetes, and also to assess the influence of disordered eating on its levels, metabolic, and reproduction features. Methods: A case-control study was conducted on 70 participants (30 patients with DM and 40 control group). 20 female patients with T1DM and 10 patients with T2DM were selected. Both groups suffer from ED and reproductive dysfunctions. Serum nesfatin-1 levels were measured. Results: Women with DM had significantly lower values of serum nesfatin-1 (ng/mL) (0.70±0.2) compared to controls (2.21±0.391), P < 0.001. Interestingly, there was a non-significant difference between female patients with T1DM (0.83±0.33) from the T2DM group (0.63±0.08) regarding serum nesfatin-1 level (p=0,332). Duration of diabetes, HbA1c, estradiol, and LH scores were independently associated with serum nesfatin-1. Remarkably, we detected that the sensitivity and specificity of serum nesfatin-1 values for distinguishing ED from the other group among female patients with DM were 96.3% and 99%, respectively. Conclusion: Nesfatin-1 levels were found to be significantly lower in female patients with DM compared to the control group and negatively correlated with cardiometabolic risk factors as well as ED and reproductive dysfunction parameters.