The present paper is dedicated to the assessment of the Light Extinction Spectroscopy (LES) technique for the characterization of submicron particles. This technique allows the measurement of the size distribution of a particle cloud starting from its Ultraviolet Near-Infrared light transmittance spectrum and is applicable in the size range going from few nanometers up to dozens of microns. The main goal of the present work is to validate the technique experimentally, using as reference both an established commercially available instrument and calibrated spherical particles. In particular, the experimental validation of the LES technique is presented for potassium chloride (MCI) and polystyrene (PS) submicron particles. In the case of MCI particles, the validation is obtained using simultaneously a Scanning Mobility Particle Sizer (SMPS), while for PS particles calibrated spheres are used. It is demonstrated that both for monodisperse and polydisperse particle size distributions, the LES technique is in a satisfactory quantitative agreement in terms of the particle size distribution function. (C) 2015 Elsevier B.V. All rights reserved.