When a gas of atoms is cooled to very low temperatures its behaviour depends on whether the atoms are bosons or fermions. Bosons can all occupy the same quantum state, whereas the exclusion principle prevents two identical fermions from having the same quantum numbers. In 1995 physicists at the JILA laboratory in Boulder, Colorado, cooled a gas of rubidium atoms, which are bosons, to temperatures so low that all the atoms condensed into the same quantum state. The creation of this Bose condensate made headlines around the world and sparked off an intense period of experimental and theoretical activity that continues today. Now another team at JILA has reported the first evidence for such quantum degenerate behaviour in a gas of fermionic atoms (Science 285 1703).