— Needles are tools widely used in minimally invasive surgery. During such procedure the localization of the needle and its tip is a challenging situation because of the needle deformations due to the interactions with tissues. To tackle this problem, instrumented needles with sensors are currently developed to allow needle reconstruction and tip localization. In conventional surgery this difficulty is overcome by medical imaging. The interest of using an instrumented needle resides in the possible dispense of medical imaging. This papers develops new methods to reconstruct needles in three dimensions and to find the locations of sensors which minimizes the error of reconstruction of the needle. A notable feature of our method is that input data are based on real needle data, that should assure a better representativity of our results. Reconstructions simulated with 22 gauges 200mm long needles data show that the localization of the needle tip is more accurate by 18% to 52% with optimal sensors positions compared to equidistant sensors positions.