This paper presents a portable, battery operated, instrument for measuring chlorophyll fluorescence on both peaks (685 and 720 nm) simultaneously. The instrument is named LEAFR (Laser Excited Automatic Fluorometer). The fluorescence is excited by a low power HeNe laser through a single optical fiber. The same fiber is also used to collect fluorescence, through a clip on probe. Fluorescence signals are detected by two photomultipliers with wavelengths selected by interference and long pass filters. An internal microprocessor controls the instrument and stores data in permanent RAM, for a later backup on an external PC. The preprocessing software allows real time display of parameters of physiological significance, as the F685/F730 ratio or fluorescence induction kinetics parameters. Some typical applications results are also briefly discussed.