InGaN multi‐quantum‐well (MQW) structure laser diodes fabricated from III‐V nitride materials were grown by metalorganic chemical vapor deposition on (111) MgAl2O4substrates. The mirror facet for a laser cavity was formed by polishing III‐V nitride films grown on (111) MgAl2O4substrates. As an active layer, the InGaN MQW structure was used. The laser threshold current density was 8 kA/cm2. At a current above laser threshold, stimulated emission was observed with a sharp peak of light output at 410 nm that had a full width at half‐maximum of 2.1 nm under pulsed current injection at room temperature. ©1996 American Institute of Physics.