The charity won the award for its sustained media coverage throughout the year, which covered the Burmese Cyclone, the third anniversary of the tsunami in South East Asia, a national flood appeal for the South West and North of England and its long-term HIV project work.
The Children's Society were also highly commended for its partnership with veteran rocker Iggy Pop and its ongoing debate on childhood as part of its The Good Childhood Inquiry.
The other finalists were the British Heart Foundation, The National Autistic Society and the RSPCA.
Meanwhile the best not-for-profit campaign went to Unity for its Wasted Youth work. The agency helped to stage the first rock gig in a UK prison to raise awareness of the fact that suicide is the biggest killer of young men in the UK.
The National Trust for Scotland and Platform PR were also highly commended for their 'Sons and Daughters of Culloden' campaign.
Other finalists included RNIB/Blue Rubicon's 'TV is good for you', World Hepatitis Alliance/Fleishman-Hillard's 'World Hepatitis Day 2008' and Marie Curie Cancer Care 'Great Daffodil Appeal'.