  We present a search for low-mass ($\leq 20 GeV/c^{2}$) weakly interacting
massive particles(WIMPs), strong candidates of dark matter particles,using the
low-background CsI(Tl) detector array of the Korea Invisible Mass Search (KIMS)
experiment. With a total data exposure of 24,324.3kg$\cdot$days,we search for
WIMP interaction signals produced by nuclei recoiling from WIMP-nuclear elastic
scattering with visible energies between 2 and 4keV. The observed energy
distribution of candidate events is consistent with null signals, and upper
limits of the WIMP-proton spin-independent interaction are set with a 90%
confidence level. The observed limit rejects most of the low mass region of
parameter space favored by the DAMA annual modulation signal.
