Borexino is a low background liquid scintillation detector acquiring solar neutrino data at the LNGS underground laboratory in Italy. Borexino is capable to perform spectral-resolved measurements of the low-energy 7Be and pep solar neutrinos. Borexino has performed the first direct measurement of the 7Be solar neutrino rate with accuracy better than 5%. The absence of day–night asymmetry of the 7Be solar neutrino rate was measured with a total uncertainty of 1%. Borexino results alone reject the LOW region of solar neutrino oscillation parameters at more than 8.5 σ CL. Combined with the other solar neutrino data, Borexino measurements isolate the MSW-LMA solution of neutrino oscillations without assuming CPT invariance in the neutrino sector. Borexino has also directly observed, for the first time, solar neutrinos in the 1.0–1.5 MeV energy range, leading to the first direct evidence of the pep solar neutrino signal and the strongest constraint of the CNO solar neutrino flux up to date.