[en] The band strengths of the 9.7 μm circumstellar silicate dust features have been obtained for a number of oxygen-rich red giant and supergiant stars whose mass loss rates have been determined using the CO (J = 2-1) and (J = 1-0) emission lines. We show that the strength of the 9.7 μm silicate dust feature is directly proportional to the mass loss rate (so long as the feature remains optically thin), indicating that the dust-to-gas ratio is approximately constant for oxygen-rich stars. The silicate dust feature thus provides a method of measuring mass loss rates for oxygen-rich red giants and supergiants, which are too distant to be detected in CO. (author)