Nucleic acids or proteins electrophoresed within a matrix or gel that immersed in a buffer provides ions needed to carry a current and for pH maintenance at a relatively constant value. Sodium dodecyl sulphate–polyacrylamide gel electrophoresis   (SDS-PAGE) utilizes SDS as an anionic detergent that causes protein denaturation that linearized protein molecules. Each molecule of SDS has the ability to binds to two amino acids. As a result, the ratio of charge to mass becomes constant for all denatured proteins in the mixture. The molecules of protein migrate toward the positive pole and separated in the gel depending only on their molecular weights. The chains of polyacrylamide are cross linked by N, N-methylene bisacrylamide comonomers and ammonium persulfate used as an initiator for polymerization as they act as radical source and N, N, N', N'- tetramethylethylenediamine (TEMED) used to catalyse the polymerization. Electrophoresis of proteins and nucleic acids by using agarose or polyacrylamide gels were illustrated in this review.