A presidential election was held in Iceland on the 30th of June 2012. The result was a victory for Ólafur Ragnar Grímsson, the incumbent president, who defeated his closest rival, Thóra Arnórsdóttir, by nearly 20% of the vote after an exciting election campaign. An opinion poll published on the 13th of April based on telephone interviews with a quota sample showed Arnórsdóttir and Grímsson with equal support. An online survey published two weeks later by the Social Science Research Institute at the University of Iceland showed Arnórsdóttir leading with 49.0%, with Grímsson on 34.8%.  Three subsequent online opinion polls, by three different survey organisations, all showed a significantly greater support for Arnórsdóttir than for Grímsson, the incumbent president.However, after Arnórsdóttir suspended her campaign as she was due to give birth, the gap narrowed as Grímsson stood alone as the leading campaigner. An average of three online polls prior to the election indicated Grímsson leading with 45% and Arnórsdóttir in second place with 37.7% ahead of four other candidates while telephone surveys showed a much greater gap of around 20% between the two candidates.  This caused a considerable public confusion – with the reliability of online panel samples being called into question.  A parallel online/telephone survey conducted from the 6th to the 19th of June showed the previously mentioned differences, with the telephone survey very close to the actual election results, with an average deviation of 0.6% compared to 3.7% in the online panel survey. The paper explores the differences between the two samples and possible explanations for the different voting intentions.