Introduction: The aim of this study was to assess the therapeutic effect and the safety of pre surgical treatment with long-acting octreotide in patients with acromegaly. Material and methods: This project was conducted in 25 centres across Poland as a non interventional, multicentre, observational study in patients with acromegaly, in which long-acting octreotide (Sandostatin® LAR®) was administered before surgery. They were 148 patients included into the study: 88 females and 60 males aged 18–86 years (51.3 ± 13.4). Results: Eighty patients completed the study (underwent tumour surgery). The CRF included: baseline visit, four follow-up visits every three months before surgery, and two follow-up visits every three months after surgery. Sandostatin® LAR® was administered every four weeks. The efficacy measures were as follows: change of growth hormone (GH) and insulin-like growth factor 1 (IGF-1) levels, number of patients fulfilling criteria of cure, and change of adenoma (micro- and macroadenomas) size during the treatment. Normalisation of GH and IGF-1 concentrations were obtained in 42.4 and 49.1% of patients at the end of medical therapy, respectively. Normalisation of GH and IGF-1 concentrations were obtained in 77.9 and 83.8% of patients after surgery, respectively. Reduction of microadenoma size was documented in 58.8% of patients, and in 70% of patients with macroadenomas at the end of medical therapy. In 74.0% of patients no pituitary tumour was shown on MRI after surgery. Conclusion: In conclusion, we have shown good surgical outcome in patients with acromegaly after pre-treatment with somatostatin analogue, and good tolerance and safety of the therapy, supporting the national recommendation for pre-surgical treatment with longacting somatostatin analogues in acromegaly patients.