Loss-of-function phenotypic analysis via interference RNA (RNAi) technology is a revolutionary approach to assigning gene function. While transcript-based methodologies commonly validate RNAi gene suppression investigations, protein-based validation is less developed. This report illustrates the potential for two-dimensional sodium dodecyl sulfate polyacrylamide gel electrophoresis (2-DE) and gel analysis to quantify protein levels following RNAi. This case study involves three glutathione transferase (GST) genes targeted by RNAi from the model organism Caenorhabditis elegans.