Abstract: A lesion location device suitable for marking a lesion in breast tissue comprises a wire, of which the first portion which has been bent to form a second portion at an obtuse or acute angle to the first portion, a 180.degree. bend and a third portion which extends adjacent the second portion and continues beyond the bend in a direction substantially opposed to that of the second portion. The bend is resiliently pivotable and forms a spring mechanism to prevent ingress of the wire once in position in the lesion. Two graduated cannulas are also provided, one with a pointed end and one with a blunt end, which are suitable for the wire to be passed into them.