This technical report defines the terminology required for luminous flux measurements. It then deals with the principles of luminous flux measurements and describes methods for the evaluation of the illuminance distribution, the measurement of luminous flux by means of an integrating sphere photometer and the determination of luminous flux via luminance, luminous intensity and luminance measurements. The report is based on and replaces CIE 025-1973, Procedures for the measurement of luminous flux of discharge lamps and for their calibration as working standards, and on the conclusions of the CIE Symposium on Light and Radiation Measurement 1981. The terminology follows that in the International Lighting Vocabulary.