Chemical compounds, which modulate enzymatic activities or those which induce specific phenotypes of interest, are valuable probes to study biological phenomena, as they allow modulation of enzymatic activities and temporal control of protein action. Here, we describe the methodology to conduct large-scale screens for chemical compounds that induce a desired phenotype in the roundworm Caenorhabditis elegans (C. elegans) using 96- or 384-well microtiter plates.