A method of and apparatus for calibration of instrumentation and provision of calibration certificates comprises a portable field operable communication device and a remote information management device in wireless communication with one another, a data store comprising information related to each instrument to be calibrated, the portable device being operable to receive calibration requests from the management device and to facilitate input of data from an instrument the subject of calibration, and the management device being operable to facilitate generation of a calibration certificate or error report subsequent to receipt of input data from the portable device.