This presentation includes the principle involved, chemistry, procedure, and application of various advance molecular biology like SDS PAGE, Western Blotting, and ELISA. SDS PAGE is widely used to analyze the proteins in complex extracts. The polyacrylamide gels are used to separate proteins. Polyacrylamide is inert, and hence, shows no interaction with the protein being separated and forms a matrix. Size of the pores in the gel can be controlled by adjusting the concentration of acrylamide. Acrylamide undergoes polymerization in order to form a gel. Hence, APS (ammonium per sulphate) & TEMED (N,N,N’,N’-tetramethylethylenediamine) are added to initiate the process of polymerization. It's application includes separation of protein mixture on separating gel and their identification using different techniques like western blotting. Western blotting, also known as immunoblotting or protein blotting, is a core technique in cell and molecular biology. In most basic terms, it is used to detect the presence of a specific protein in a complex mixture extracted from cells. Western blots are effective in detecting low nanogram to low picogram amounts of target protein, depending on the antibodies used and the detection substrate chosen. If the target is suspected to be of very low abundance, or if there is no detectible signal on the blot, then it may be necessary to concentrate, immunoprecipitate, or fractionate the starting material. This technique is used to study cell signalling pathways, cell cycle pathways, drug action pathways, protein-protein interaction. ELISA (enzyme-linked immunosorbent assay) is a plate-based assay technique designed for detecting and quantifying peptides, proteins, antibodies, and hormones. In an ELISA, an antigen must be immobilized to a solid surface and then complexed with an antibody that is linked to an enzyme. Detection is accomplished by assessing the conjugated enzyme activity via incubation with a substrate to produce a measurable product. The most crucial element of the detection strategy is a highly specific antibody-antigen interaction. ELISA begins with a coating step, in which the first layer, consisting of a target antigen or antibody, is adsorbed onto a 96-well polystyrene plate. This is followed by a blocking step in which all unbound sites are coated with a blocking agent. Following a series of washes, the plate is incubated with enzyme-conjugated antibody. Another series of washes removes all unbound antibody. A substrate is then added, producing a calorimetric signal. Finally, the plate is read. It's types include Direct ELISA, Indirect ELISA, Sandwich ELISA and competitive ELISA. This technique is used to determine serum antibody concentrations, potential food allergens (milk, peanuts, almonds), detection of antigens and antibodies, disease outbreaks.