The behaviour of fillers (carbon black, precipitated silica, ZnO and CaCO3) in rubber crosslinked conventionally or with ionic and complex crosslinks was studied. Use of monoallyl maleate as a coagent of peroxide vulcanisation of EPM in presence of alkaline fillers leads to formation of crosslinks with ionic structure. Zinc chloride added to NBR forms complex crosslinks with participation of nitrile groups, which act as ligands. It is shown that the strongest reinforcing effect had fillers in vulcanizates containing ionic crosslinks, particularly if ZnO and CaCO3 were used. It is established that the activity of ZnO is also rather high in ZnCl2-containing NBR vulcanizates; the behaviour of silica and carbon black is less dependent on the structure of crosslinks.