Abstract: A method and a device for recognition of paravasal bleeding upon a supplying of blood to a vascular access via a line and/or upon the removal of blood from a vascular access via a line, particularly paravasal bleeding during extra-corporeal blood treatment, such as for hemodialysis, hemofiltration or hemodiafiltration is provided. A device for extra-corporeal blood treatment, particularly for hemodialysis, hemofiltration or hemodiafiltration, comprising a device for recognition of paravasal bleeding is also provided. The method and the device are based on the change of arterial pressure in the arterial branch or the venous pressure in the venous branch of the extra-corporeal circuit being registered during the extra-corporeal blood treatment.