Immune checkpoint inhibitors (ICIs) have revolutionized cancer therapy, but their use is associated with a spectrum of immune-related adverse events (irAEs), including endocrine disorders. This retrospective study analyzed 139 cancer patients treated with ICIs between 2016 and 2022 to investigate the incidence, timing, treatment modalities, and impact of ICI-related endocrine side effects. The most common endocrine irAE was hypothyroidism (65,5%), followed by hyperthyroidism (2,3%), hypophysitis (8,6%), and diabetes mellitus (0,7%). These disorders typically emerged within the first six months of ICI therapy. Most cases were managed conservatively or with hormone replacement therapy. Interestingly, patients who developed endocrine irAEs exhibited a higher objective response rate (ORR) and clinical benefit rate (CBR) compared to those without irAEs. This suggests a potential association between irAEs and improved clinical outcomes. However, the development of irAEs can significantly impact patients’ quality of life and may necessitate dose reduction or treatment interruption. In conclusion, endocrine dysfunction is a significant toxicity of ICI therapy. Early recognition, prompt diagnosis, and appropriate management are crucial to minimize their impact on patient health and quality of life. Further research is needed to elucidate the underlying mechanisms and to identify predictive biomarkers for irAE development.