Low‐loss AlxGa1−xAs waveguides withx=0.1 andx=0.25 have been fabricated by molecular beam epitaxy. Losses are determined for bothn‐ andp‐type waveguides using a combination of Raman scattering and transmission measurements. These waveguides have optical losses ⩽1.5 cm−1between 1.1 and 1.4 eV, the energy of the GaAs double heterostructure laser, and are comparable to similar waveguide structures grown by liquid phase epitaxy.