The backward branch of the electrostatic ion‐cyclotron wave has been observed for the first time. The wave, which was driven by a phased antenna structure inserted in a neon plasma, exists in the parameter ranges 2Ti/mi≪(&ohgr;/k∥)2≪2Te/me,n&OHgr;i<&ohgr;<(n+1)&OHgr;i,Te≳Ti, and &ohgr;pi>&OHgr;i. Double‐tip probe interferometry data agree with the theoretical dispersion relation. The antenna couples into the wave more readily on the side of the antenna where it has its smallest wavenumber.