While a variety of light‐detecting devices have been made with HgCdTe, little has been done to apply this technology to light‐emitting devices. We report here the successful fabrication and operation of the first HgCdTe injection laser. This stripe‐geometry double‐heterostructure laser was operated under pulsed current at temperatures between 40 and 90 K. At 77 K, the emission wavelength was 2.86 &mgr;m with a linewidth of 0.3 meV, and the pulsed threshold current density was 625 A/cm2. The double heterostructure, with a 1.4‐&mgr;m‐thick active layer, was grown andinsitudoped by molecular beam epitaxy (MBE). Thep+andn+confinement layers were doped with arsenic and indium, respectively.