Present work investigates effects of application of different boundary layer control mechanisms on 2-D incompressible laminar flow around circular cylinder at different ?ow conditions. It focuses unsteady cases with its transient conditions. Unsteady Navier-Stokes equations are deployed. In tangential blowing from cylinder surface, both point blowing and span blowing are considered to study variations of lift, drag by varying blowing port positions and intensity of blowing. Effects on unsteadiness are also examined. In case of rotation of cylinder surface for controlling boundary layer, lift and drag are inves¬tigated by varying rotational speeds. Rotation has been found to have strong in?uence on ?ow and mode of vortex shedding gets changed from the surface. Rotational oscillation of cylinder surface, both for Lock-on and non-Lock-on cases have been studied. Frequency and amplitude of rotational oscillation are made to vary to investigate effects on the lift and drag. It reveals that the effect of amplitude of oscillation on drag is complicated and ratio of forcing frequency and natural frequency affects ?ow conditions substantially.