The potential merits of CsI(TI) scintillating crystals for Dark Matter experiments make it a subject of recent interest. The scattering signatures by neutrons on a CsI(Tl) detector were studied using a neutron beam generated by a 13 MV Tandem accelerator. The energy spectra of nuclear recoils from 7 keV to 132 keV were measured, and their quenching factors for scintillating light yield were derived. The data represents the first confirmation of the Optical Model predictions on neutron elastic scatterings with a direct measurement on the nuclear recoils of heavy nuclei. (C) 2002 Elsevier Science B.V. All rights reserved.