A novel method to disperse single-walled carbon nanotubes (SWNTs) in water using self-aggregating peptides was demonstrated. SWNT dispersion was performed by the addition of water to solid mixtures of SWNTs and the peptides, in addition to subsequent sonication processes. Spectroscopic and microscopic analyses revealed that our method successfully disentangled and dispersed larger amounts of SWNTs with better dispersion stability as compared to conventional methods.