The award was unveiled in Copenhagen, home to an iconic statue of Hans Christian Andersen's fairytale character the Little Mermaid, on the sidelines of United Nations talks on fighting global warming.
"Monsanto was nominated for promoting its genetically modified (GM) crops as a solution to climate change and pushing for its crops to be used as biofuels. The expansion of GM soy in Latin America is contributing to major deforestation and greenhouse-gas emissions," the nomination ran.
In a web-based poll of 10,000 people, some 3,700 tipped Monsanto as the most aggressive and inappropriate lobbyist, ahead of oil giant Shell (1,800 votes) and the American Petroleum Institute (1,400 votes).
"Monsanto has attracted thousands of votes from individuals who are outraged that such an environmentally-damaging form of agriculture should be put forward to tackleclimate change," said organizer Paul de Clerk of environmental group Friends of the Earth.
"Big business must not be allowed to sabotage action against climate change by promoting their vested interests. All the candidates for the ‘Angry Mermaid' award have lobbied to protect their own profits and prevent effective action to tackle climate change," he said.
The award was set up by Friends of the Earth and five other groups to "highlight those business groups and companies that have made the greatest effort to sabotage the climate talks, and other climate measures, while promoting, often profitable, false solutions."
Hundreds of activists have descended on Copenhagen in recent days to push for a worldwide deal on fighting climate change and cracking down on pollution.
The event has spawned a number of ironic awards targeting groups seen as hostile to a deal.
As well as the Angry Mermaid, for example, environmentalists have created a "fossil of the day" prize to target the country or company which is seen as having done most to block progress.