GaInAsSb/GaSb double-heterostructure (d.h.) lasers were fabricated by liquid-phase-epitaxial growth. C.W. operation was realised at 80 K with a wavelength of 2.0 μm. From measurement of laser thresholds as a function of temperature, it was shown that threshold currents for pulsed operation are described by the expression I(T) ∞ exp (T/T0), where T0 = 58 K.