Background: Studies have shown that health-related quality of life (HRQoL) of patients with neuroendocrine tumors (NET) is lower compared to the general population in the US and Norway. Secretory symptoms associated with functional NET (diarrhea/flushing) contribute to worsened HRQoL but may be controlled with the somatostatin analog octreotide long-acting repeatable (LAR). To date, there have been limited assessments of specific drug effects on HRQoL in patients with NET. The purpose of this study was to assess the effect of octreotide LAR treatment on HRQoL. Methods: 93 Hungarian patients with gastroenteropancreatic NET who were treated with octreotide LAR participated in a multicenter observational study from 2005 to 2007. At study entry and 4 quarterly follow-up visits, patients completed the European Organization for Research and Treatment of Cancer Quality of Life Questionnaire-Core 30 (EORTC QLQ-C30) questionnaire. A mixed model was used to analyze the data and confirm significance. Results: 91 patients (mean age = 61 years) were evaluable for QoL assessments. Overall, patients reported improvements in diarrhea, global health status, emotional functioning, and financial difficulties but worsening in role functioning, pain, and insomnia. There were some differences in trends, depending on the tumor site, but diarrhea still improved in all patient categories. Women reported lower global health status compared to men, including more fatigue, nausea/vomiting, pain, dyspnea, and constipation. Elderly patients >70 years did not report any lessening of overall global health status scores compared to younger patients; older patients did experience less nausea/vomiting and pain but more constipation and diarrhea. In addition, patients diagnosed <2 years had slightly lower global health status than patients diagnosed >2 years earlier. Conclusions: Patients with NET who were treated with octreotide LAR had improvements in global health status and diarrhea. Interesting trends were noted in different patient populations, depending on tumor site, gender, or age. Additional analysis is planned to assess changes as measured by the GI NET disease-specific module of EORTC that was also applied to patients.