Numerous experiments have searched for neutrinoless double beta decay. The best-performing experiments have a high mass of the decaying isotope and low backgrounds, with some experiments able to perform particle discrimination and electron tracking. In order to remove backgrounds from cosmic rays, most experiments are located in underground laboratories around the world.
Recent and proposed experiments include:
* Completed experiments:
** Gotthard TPC
** Heidelberg-Moscow, Ge detectors (1997–2001)
** IGEX, Ge detectors (1999–2002)
** NEMO, various isotopes using tracking calorimeters (2003–2011)
** Cuoricino, Te in ultracold TeO crystals (2003–2008)
* Experiments taking data as of November 2017:
** COBRA, Cd in room temperature CdZnTe crystals
** CUORE, Te in ultracold TeO crystals
** EXO, a Xe and Xe search
** GERDA, a Ge detector
** KamLAND-Zen, a Xe search. Data collection from 2011.
** , using high purity Ge p-type point-contact detectors.
** XMASS using liquid Xe
* Proposed/future experiments:
** CUPID, neutrinoless double-beta decay of Mo
** CANDLES, Ca in CaF at Kamioka Observatory
** MOON, developing Mo detectors
** AMoRE, Mo enriched CaMoO crystals at YangYang underground laboratory
** nEXO, using liquid Xe in a time projection chamber  
** LEGEND, Neutrinoless Double-beta Decay of Ge.
** LUMINEU, exploring Mo enriched ZnMoO crystals at LSM, France.
** NEXT, a Xenon TPC. NEXT-DEMO ran and NEXT-100 will run in 2016.
** SNO+, a liquid scintillator, will study Te
** SuperNEMO, a NEMO upgrade, will study Se
** TIN.TIN, a Sn detector at INO
** PandaX-III, an experiment with 200 kg to 1000 kg of 90% enriched Xe
** DUNE, a TPC filled with liquid Argon doped with Xe.