This work reports the formation of stable nanoassemblies of short pentapeptides LKLKL (pepI) and their mutated sequence LKKLL (pepII) obtained from their Langmuir-Blodgett films transferred onto hydrophilic and hydrophobic silicon substrates. The adsorption and assembly of the LB films of these peptides on solid surfaces have been studied by quartz crystal microbalance, surface plasmon resonance, and scanning electron microscopy. Both pepI and pepII assemble into nanosized ribbons, with diameters around 20-25 nm and lengths greater than 5 mu m on hydrophobic surface, and tend to aggregate on hydrophilic surfaces with pepII showing twisted structures. Circular dichroic spectra of the films on a hydrophobic surface showed formation of a beta-sheet-like structure, while the corresponding solution spectra did not show any specific secondary structure. Our results demonstrate the formation of a two-dimensional dense array of nanoassemblies with either vertical or horizontal patterns from such short peptides that may find application in nanotechnology.