Two synthetic routes to surface-aminated polypyrrole-silica nanocomposite particles have been investigated. Route 1 involved the initial synthesis of homopolypyrrole-silica particles as described previously, followed by surface amination using 3-aminopropyltriethoxy-silane. In Route 2 aminated polypyrrole-silica particles were synthesized directly by copolymerising an N-substituted aminopyrrole comnonomer with pyrrole in the presence of an ultrafine silica sol. Both types of aminated particles were characterized in terms of their particle size and morphology, long-term colloid stability and degree of amination using transmission electron microscopy, disc centrifuge photosedimentometry and zeta potential measurements, respectively.