Background: The thyroid gland plays a vital role in the regulation of many physiological processes, including kidney function. Aim: The purpose of this study was to investigate the relationship between thyroid-stimulating hormone (TSH) and kidney function in male and female patients with hyperthyroidism, as well as in healthy control subjects. Method: A total of 60 participants from Najaf city, Iraq, were included in the study. This included 10 male and 10 female control subjects, as well as 20 male and 20 female patients with hyperthyroidism. Blood samples were collected from all participants and analyzed for TSH, urea, and creatinine levels. Result: The results showed a significant increase in TSH levels in both male and female patients with hyperthyroidism compared to control subjects. Urea levels were also significantly higher in hyperthyroidism patients compared to controls, while creatinine levels were not significantly different. In addition, there was a significant difference in the effects of TSH on kidney function between male and female patients with hyperthyroidism. Female patients with hyperthyroidism had significantly higher levels of urea and lower levels of creatinine compared to male patients with hyperthyroidism. These findings suggest a direct effect of TSH on kidney function and highlight the need for regular monitoring of kidney function in individuals with hyperthyroidism, particularly women. Further research is needed to fully understand the mechanisms behind the gender differences observed in this study and to develop targeted interventions for both men and women with thyroid disorders. Conclusion: our study provides valuable insights into the relationship between TSH and kidney function and highlights the need for multidisciplinary care and targeted interventions for individuals with thyroid disorders to prevent or minimize the risk of kidney dysfunction.