Hippocampal-dependent neurocognitive functions, including learning, memory and spatial information processing, could be affected by brain radiotherapy. Aim of the present study is to evaluate the dose to omolateral and contralateral hippocampus (O-H, C-H, respectively) during Stereotactic Radiotherapy (SRT) or Radiosurgery (SRS) for brain metastases (BM). Patients eligible for SRS/SRT treatment had a number of BM <5, with a size ≤30mm, Karnosky Performance Status (KPS) ≥ 80 and a life expectancy over 3 months. Gross Tumour Volume (GTV) was delineated by the fusion between Magnetic Resonance Imaging and Computed Tomography. A Planning Target Volume (PTV) was obtained from GTV by adding a 2-mm isotropic margin. The total dose ranged between 18-27 Gy in 1-3 fractions. For each BM, a volumetric modulated arc therapy plan was generated with one or two arcs and hippocampus sparing was not considered during optimizations phase. For the dosimetric evaluation of O-H and C-H, the Dmedian, Dmean, D0.1cc and the V1Gy, V2Gy, V5Gy and V10Gywere analyzed. From April 2014 to December 2015, 81 BM in 41 patients were treated with SRS/SRT and selected for the present analysis. The average value of PTV dimension and hippocampus volumes were (5.8 + 9.5) cc and (1.1 + 0.3) cc, respectively. For the O-H, the average values of Dmedian, Dmean and D0.1cc were (1.5 + 3.65) Gy, (1.54 + 3.6) Gy, (2.2 + 4.7) Gy, respectively, while the V1Gy, V2Gy, V5Gy and V10Gy values were (25 + 40) %, (18.9 + 35) %, (8.9 + 25.3) % and (2.1 + 11.8) %, respectively. For the C-H, the average Dmedian, Dmean and D0.1cc were (0.7 + 1.5) Gy, (0.7 + 1.4) Gy, (0.9 + 1.8) Gy, respectively, while the average values of V1Gy, V2Gy, V5Gy and V10Gywere (18 + 35) %, (10.2 + 27.7) %, (2.8 + 15.4) % and (1.4 + 11.6) %, respectively. The differences between O-H and C-H, in terms of received dose, were statistically significant (p=0.03). Moreover, the PTV dimension (>5cc or >6cc) did not influence the dose of hippocampus (p= 0.06; 0.2, respectively). During SRT/SRS treatments for BM, hippocampus received a very low dose and its clinical significance seems to be negligible, even if it is still under investigation. However, considering the increasing use of SRS/SRT for multiple BM, including also patients with up to 10 BMs, the dose to hippocampus need to be seriously evaluated in the treatment planning.