Biological self-assembly systems lie at the interface between molecular biology, chemistry, polymer science and engineering. The key elements in molecular self-assembly are chemical complementarity and structural compatibility. Several types of self-assembling peptides have been engineered. Type I peptides undergo intermolecular self-assembly, type II peptides undergo self-assembly and disassembly, i.e. intermolecular and intramolecular self-assembly under the influence of various conditions. Type III peptides undergo self-assembly on to surfaces. These self-assembling peptide systems are simple, versatile and easy to modify and to produce. These systems represent a significant advancement in the molecular engineering of protein fragments for diverse technological innovations.