This is the partial list of countries which will take part in IMO 2010: http://www.imo-official.org/year_reg.aspx
At the time of writing, 102 countries have registered to participate. The list will be updated daily as countries confirm their participations and register their contestants. Some countries have finalized their teams — as of now, Australia, Cambodia, Ivory Coast and Uzbekistan have registered the full team. The Malaysia team will be finalized in early May, after our final training camp from 30 April to 4 May. Good luck to all 16 of you.