ANAIS is a particle detector experiment designed to detect dark matter. ANAIS stands for Annual modulation with NAI Scintillators. Its main goal is the direct detection of the dark matter through its scattering off the target nuclei in a radiopure NaI(Tl) crystal. This dark matter signal should be annually modulated by the change in the relative velocity of WIMP-nucleus, a result of the rotation of the Earth around the Sun.

ANAIS is the scaled conclusion of feasibility studies carried out with different prototypes by the University of Zaragoza group at the Canfranc Underground Laboratory, Spain. The complete experiment will use more than one hundred of kg of ultrapure sodium-iodine NaI(Tl) crystals. Data recording began at the end of October 2012 using 25 kg in two prototype detectors as the last step before launching the larger experiment.[2][3] A third detector was installed in 2014[4] showing a better radiopurity allowing the commissioning of the full experiment expected by mid-2016.[5]

DAMA/NaI and DAMA/LIBRA,[6] experimental efforts performed at the Gran Sasso National Laboratory, accumulated more than thirteen annual cycles of data (also with NaI scintillators), obtaining a positive signal. Comparison of that result with negative results from other targets and experimental techniques is strongly model dependent. ANAIS (adopting the same target and technique that DAMA/LIBRA) appeared in the last roadmap of ApPEC[8] (Astroparticle Physics European Coordination) to allow testing with an independent experimental set-up and in a model-independent way.