Abstract. Twenty years ago, we predicted that primordial black holes would form via the gravitational collapse of matter associated with peaks in the spectrum of fluctuations, and that they could constitute all of the dark matter today. More recently, we predicted the mass distribution of PBH, which peaks at 50 Msun and whose tails could be responsible for the seeds of galaxies. LIGO has recently detected gravitational waves from the inspiraling of two 30 Msun black holes. We propose that LIGO has actually detected dark matter in the form of PBH, and predict that within 10 years, an array of GW detectors (i.e. LIGO, VIRGO, KAGRA, LIGO-India, etc.) could be used to determine the mass and spin distribution of PBH dark matter with 10% accuracy.