Cowpea chlorotic mottle virus (CCMV) capsids were used to encapsulate Prussian blue (PB) particles based on electrostatic interaction. A negatively-charged metal complex, hexacyanoferrate (III), was entrapped inside the capsids through the disassembly/reassembly process under a pH change from 7.5 to 5.2. The loaded capsids reacted with a second Fe(II) to fabricate PB particles. The synthesis of PB in CCMV capsids was confirmed by a unique colour transition at 710 nm and by size-exclusion FPLC. Transmission electron microscopy images of PB-CCMV biohybrids presented discrete spherical particles with a relatively homogeneous size. Dynamic light scattering of PB-CCMV showed two peaks of 29.2 +/- A 1.7 nm corresponding to triangulation number T = 3 particles, and 17.5 +/- A 1.2 nm of pseudo T = 2 particles. The encapsulation and crystallization of PB in CCMV provided an efficient method for the self-organization of bimetallic nanoparticles.