A steerable intravascular catheter is disclosed which includes an elongated sheath having a tubular body wall defining a central lumen and a deflectable distal end portion, a pair of laterally opposed elongated pull wires extending through the tubular body wall of the sheath and terminating within the distal end portion thereof, and a handle assembly having a longitudinal axis and operatively associated with a proximal end portion of the sheath, the handle assembly including an rotatable control knob for controlling bi-directional deflection of the distal end portion of the sheath, wherein bi-directional angular rotation of the control knob about the longitudinal axis of the handle assembly effectuates corresponding reciprocal axial movement of the laterally opposed pull wires in opposed axial directions and corresponding bi-directional deflection of the distal end portion of the sheath.