This work deals with the influence of strontium oxide (SrO2) in the dielectric properties of the Ba2Ti9O20 ceramics as microwave oscillators for telecommunications applications. The main requirements of these dielectric resonators are the high selectivity and stability in frequency, the high value of both the dielectric constant (6) and of the quality factor (Q), as well as the low temperature coefficient of resonance frequency (tau(f)). The ceramics were prepared using suitable powder mixtures, without and with SrO2 addition, varying the content from 0.2 to 1.0 mol %. The powders were mixed, compacted by uniaxial and isostatic pressing, producing cylindrical samples with specified dimensions in order to obtain dielectric resonators operating at frequency range around 7.0 GHz. Finally, they were sintered at 1250 degrees C for 6 hours and 1360 degrees C for 6 hours. The ceramics characterization was carried out using X-ray diffraction technique (for the formation study of the Ba2Ti9O20 chemical compound), and scanning electron microscopy - SEM (for microstructure densification degree and grain size analyses). The dielectric parameters in microwaves (F,, Q and tau(f)) were measured using a suitable microwave system specially mounted to accomplish such measurements. SEM analyses showed a high densification degree and a grain size increase with the amount of SrO2 added to the ceramics. This fact has increased the quality factor due to dielectric losses, although the dielectric constant was kept practically unchanged.