Abstract We present a study of high-power characteristics of edge-emitting lasers based on quantum well-dots (QWD) in a pulsed regime. QWD-based lasers with 2 and 5 active layers emitting at ∼1.1 μm provided maximal optical power of 39 W limited by the pulse current source available. We have investigated the lasing spectra and shown that under the injection current above 20 kA/cm² the active region overheats approximately by 0.5°C per 1 kA/cm² during 100 ns current pulse. The active region overheating correlates well with the reducing of the differential efficiency of our devices. We believe that maximal pulse optical power of the QWD-based lasers is limited mainly by our laser wafer design rather than by the QWD active media properties.