The charities have announced that VASD will become part of QEF at the end of the month, when QEF trustees are due to rubber-stamp the move.
VASD, which employs four staff on a part-time basis and whose income for 2010/11 is listed as £164,000 on the Charity Commission website, will retain its identity and become "part of the QEF family", a QEF spokesman said. "That’s not to say it will not change in the future," he added.
The spokesman said that QEF, which has an income of about £12m a year and employs about 250 people, was in negotiation with other local disability charities with a view to possible mergers, but said he was unable to name them at this stage.
Roger Glenwright, chair of VASD, said: "The challenging economic climate and uncertain funding for our future work was an important reason to merge. But we do believe that we are better together and will provide support to more disabled people and their families."
Jonathan Powell, chief executive of QEF, said he was "delighted that these two long-established Surrey charities with such an amazing history have merged.
"We trust that together we can add real value to these vital services."