A catheter anchoring or securement device and system in combination with or for securing a catheter system to a patient's skin in a fixed position, the invention having a flexible anchor sheet member having an adhesive backing that adheres the flexible anchor sheet member to the patient's skin, a catheter receiving body mounted to the flexible anchor sheet member, and releasable securing means comprising a cover or closure member covering the catheter receiving body, wherein the catheter receiving body is provided with a cavity or recess, the peripheral configuration of which corresponds to the footprint configuration of the catheter body member. The cavity has an axially-oriented channel extending the full width of the flexible anchor sheet member and opposing sets of retention walls defining lateral recesses, the combination of which precludes relative movement of the catheter fitting in all lateral directions.