Low-frequency oscillations are unstable in a wide range of stellarmodels and have been detected in a number of B-type stars. For suchmodes, even a moderate rotation significantly affects amplitudedistribution over stellar surface and hence their visibilityconditions. Adopting the traditional approximation, we study effectsof rotation on relative amplitudes in photometric passbands and inradial velocity. We present numerical results for unstable modes ina selected stellar model of a 6 M๏ main sequence star. Thegoal is to show how observable amplitudes, which are tools for modeidentification, depend on the rotation rate and on the aspect angle.