The microwave-absorbing properties of La1-xSrxMnO3 (x = 0.4, 0.5, 0.6 and 0.7) powders have been studied in the frequency range of 8-12 GHz at room temperature. The optimal absorption can be achieved and microwave loss peak is at 25 dB for x = 0.4 sample. Both tan 6, and tan 5 measurements show that the absorption can be attributed to magnetic and dielectric losses. The microwave loss peak corresponds to the maximum dielectric loss tangent tan delta(e) near 10.5 GHz. The sample having lower resistivity exhibits a larger microwave-absorbing ability, which can be considered as another origin for the microwave absorption. (C) 2002 Elsevier Science B.V. All rights reserved.