Black-hole microquasars generally show low frequency quasi periodic oscillations (LFQPO) in their hard and intermediate spectral states. LFQPO are oscillations in the hard-powerlaw part of the X-ray spectra, where the oscillation frequencies are in the range of just under 1 Hz to about 20 Hz, but generally around few Hz. LFQPOs have been extensively studied. Even relations between QPO frequency and the spectral index of the power law tail have been emperically obtained by numerous observations. However HFQPO (>50 Hz) have been detected only in a few observations. In this talk we show that shock oscillations in transonic accretion discs around rapidly rotating blackholes can explain both low- and high-frequency QPOs.