Abstract: A steerable catheter includes a handle and a catheter tube, the tip of which may be selectively curved by an operator. Three elongated, substantially flat planar shims are juxtaposed in sandwiched relation and mounted within the tip of the catheter tube for movement relative to one another remotely from the catheter handle. When one of the three shims slides relative to the other two, the catheter tube tip bends to attain a user-controlled curvature. A curvature controlling and locking mechanism in the handle permits the operator to readily and accurately effect separate coarse and fine adjustments to the curvature of the catheter tip.