Purpose The aim of this study is to analyze peptide receptors radionuclide therapy (PRRT) effectiveness in functioning malignant insulinomas poorly responsive to conventional therapies, by reviewing literature reports and combining them to our Center experience. Method Due to the rarity of this tumor, most literature is based on case reports. Overall, eight case reports and case series published between 2008 and 2019 were analyzed. A total of 34 patients affected by functioning metastatic insulinomas were evaluated. Among these, 33 patients were treated with 177Lu-DOTATATE and 1 patient received Indium-111 Octreotide. Results In terms of tumor growth control, 2 patient showed complete response to therapy (5.8%), 19 patients achieved partial response (55.9%), 8 patients presented stable disease (23.5%), and 5 patients progressed (14.7%). In terms of symptoms control, 24 out of 34 of patients (70.6%) reported a better glycemia level control, which is an important result that leads to a significant improvement of patients’ QoL. However, all these case reports profoundly differ between each other, in terms of treatment scheme, eligibility criteria and previous therapies. Therefore, it is extremely complex to statistically compare these studies and objectively evaluate the efficacy of this therapy in insulinomas, although, overall, it would seem to have a significant impact on the patient's QoL, PFS and tumor management. Conclusions In conclusion, PRRT resulted to be a very promising treatment for inoperable malignant insulinomas, in terms of patients’ quality of life improvement, clinical symptoms and tumor growth control. Further studies are needed, especially to evaluate its possible application as first-line therapy, in association with conventional therapies, which could lead to even better and longer-lasting results.