The award in the investor relations category came at the 2010 Chartered Institute of Public Relations (CIPR) Excellence Awards in London.
Judges described the PR campaign as "well planned and measured" and "strongly executed", saying it "delivered the desired results and enhanced Centrica's reputation with key commentators".
Director of group media relations Mish Tullar said: "This recognition is testament to the great teamwork and meticulous planning involving many people across the Centrica who worked on the Venture deal and helped us keep on the front foot with the media."
Last year's £1.3 billion acquisition of Venture, an oil and gas company specialising in ‘orphaned' fields, led to the formation this year of Centrica Energy Upstream, which is based in Aberdeen.
The CIPR, celebrating the awards' 25th year, said a study by Leicester University showed that award-winning companies experience an improved financial performance after just one year of winning their first award. After three years, the benefits were even greater.
What the judges said about the Venture campaign
A well-planned and measured campaign, strongly communicating Centrica's messaging and rationale for the acquisition through financial commentators to ensure the strategy was clearly understood. Successful targeting of Scottish media garnered support from regional Venture employees and other stakeholders.
Overall, favourable media and analyst coverage illustrated the benefits of the deal, as well as senior management's skill in managing the process. A strongly executed campaign, which delivered the desired results and enhanced Centrica's reputation with key commentators.