By supporting the initiative, the ESA and its members must not use print, TV or internet adverts to target children aged under 12 unless there is scientific backing.
Furthermore all advertising in primary schools must be avoided unless specifically requested by the institution.
From January next year the ESA will monitor members to ensure rules are adhered to.
UK watchdog, Ofcom, has said food advertising and school vending machines are key influences to children's food choices.
The EU Pledge was launched in December 2007 following warnings of the dangers of advertising high fat, sugar and salt products to children.
Initial members included Burger King, Coca-Cola, Danone, General Mills, Kellogg, Mars, Nestle and Unilever.
Other ESA members are Intersnack, Lorenz Snack World and Procter & Gamble.