An experimental study of the vortex-induced vibrations of a pivoted circular cylinder was conducted to investigate the regions of lock-in between the vortex shedding and body vibration frequency for uniform and shear flow in Reynolds number ranges from 16,500 to 22,000. A rigid circular cylinder pivoted at the top by a bearing and stiffened by two transverse springs at the bottom was mounted in a wind tunnel. The cylinder was allowed to oscillate only in the cross-flow direction. The lock-in region was approached by varying the flow velocity. Measurements were made of the width of the frequency lock-in range, response amplitude, displacement time series and power spectral densities of the wake shedding for different Re numbers.