An endoscopic surgical blade is disclosed. The blade is of a low-profile design, having a downward angled cutting surface that is radiused at its upper end. The blade is part of an endoscopic knife assembly which also contains a knife tube. The endoscopic knife assembly is for use in endoscopic surgery by insertion of the assembly through a slotted cannula. The knife tube is hollow and allows the insertion of an endoscope for viewing of the surgical procedure. A method for a performing an operative procedure on a target tissue in a subject using an endoscopic knife assembly having a low-profile, downward angled blade is also described.