We report preparation Of stimuli-responsive bicomponent polymeric Janus particles and investigation of their switching behavior. The first polymer was immobilized on one side of silica particles using the surface-initiated atom transfer radical polymerization, "grafting from" approach. The second polymer was immobilized using the "grafting to" method by reaction between reactive terminating groups of polymer chains and functional groups on the particle Surface. On the example of mixed oppositely charged polyelectrolyte Janus particles decorated with poly(acrylic acid) and poly(2-vinylpyridine) chains, we demonstrate stimuli-responsive aggregation/disaggregation behavior upon pH changes.