The GERDA experiment searches for neutrinoless double beta decay in $^{76}$Ge. In its first phase, GERDA collected 21.6 kg$\cdot$yr of exposure with a background index (B.I.) of 0.01 counts/(keV$\cdot$kg$\cdot$yr). No signal was observed and a lower limit for the half-life of the process has been set to $2.1 10^{25}$ yr (90% C.L.).
The apparatus has been upgraded to the Phase II configuration with 30
additional custom made BEGe detectors with better energy resolution and better pulse shape discrimination potential. For a further reduction of the B.I. light detectors have been installed to veto background events which produce scintillation light in the liquid argon surrounding the Ge detectors.
GERDA Phase II is currently taking data with 37 HPGe detectors enriched in $^{76}$Ge for a total mass of 35 kg. The goal of Phase II is to increase the half-life sensitivity to the order of $10^{26}$ yr, this will require 100 kg$\cdot$yr exposure with a B.I. of $10^{-3}$ counts/(keV$\cdot$kg$\cdot$yr).