A medical or a dental instrument comprises an operative portion (101) for operations according to the purpose of use of the instrument, a center portion (103) mechanically connecting to the operative portion, and a radio frequency identifier (106) located on the center portion and capable of being read from a distance of the instrument. The instrument further comprises a tubular handle portion (104) provided to surround the radio frequency identifier and at least a part of the center portion, the tubular handle portion being cast on the instrument so that the material of the tubular handle portion is adhered to the material of the center portion. Thus, the tubular handle portion acts not only as the handle portion but also as at least a part of a fixation system attaching the radio frequency identifier to the instrument. An instrument of such construction is easy to keep hygienic.
