Continuous-wave (cw) operation of InGaN multiquantum-well-structure laser diodes (LDs) was demonstrated at 233 K. The threshold current and voltage of the LD were 210 mA and 11 V, respectively. During room-temperature cw operation, the LDs were easily broken within one second due to heat generation. At 233 K, the lifetime of the LDs was longer than 30 min, and the emission spectra could be measured under cw operation. Only a single peak was observed under cw operation with increasing forward current above the threshold current. The characteristic temperature of the threshold current of the LDs was 162 K.