Post-Transcriptional Gene Silencing and RNA interference (RNAi) are terms describing the specific suppression of genes by complementary dsRNA. High-efficiency transfection is an essential first step for achieving effective gene knockdown. Non-viral transfection include chemical-transfection and electrotransfection. For a particular cell line, select the appropriate transfection method is very important. In this study, we compared a variety of commercially available reagents and electrotransfection, approaches to define methods for efficient delivery of siRNA to NB4 cells. Fluorescently-labelled siRNA were tested. We report that different methods have different effects. The results provide guidelines for optimal siRNA-mediated knockdown in the NB4 cells.