Delingpole beat international competition to take the $3,000 prize, organised by the International Policy Network (IPN), which recognises writers whose work promotes and defends "the principles and institutions of the free society".
It is the second year running in which a Telegraph blogger has taken the online award. In 2009 controversial MEP Daniel Hannan won the prize for his blog for the title.
"This is great news. James' posts on the Climategate scandal made a huge international impact on the debate over global warming, raising serious questions about the scientific basis of some of the more extravagant predictions of environmental apocalypse," says Telegraph blogs editor Damian Thompson in a post on Delingpole's win.
Bret Stephens of the Wall Street Journal won the $15,000 print journalism award for which two previous Bastiat winners, Financial Times journalist Tim Harford and freelancer Jamie Whyte, were shortlisted.
The winners were announced at a ceremony in New York last night.