Purpose Hand-held gamma-probes are used for the identification of the sentinel node location during intra-operative radio-guided surgeries. Various gamma-probes, which use different detectors, collimation and electronics, are available on the market. Spatial resolution, sensitivity and angular resolution of the probes are believed to be determinant for the success of the identification of the sentinel node during radiosurgery. Materials and Methods We compared the above-mentioned performances of sentinel probes from six manufacturers available in the European market by means of the NEMA NU3-2004 standard, which allows the users to evaluate the probes during a situation which mimics a intra-operative radio-guided surgery. Results and conclusion This study presents a summary of characteristics to be expected when using the tested gamma-probes during intra-operative radio-guided surgeries, with particular emphasis on breast cancer sentinel node surgery. The results from this study can be used as the guidance for the selection of a sentinel lymph node probe. Nucl Med Commun 30:854-861 (C) 2009 Wolters Kluwer Health | Lippincott Williams & Wilkins.