Occam will use its warm donor exchange programme Reciprocate to provide data for the upcoming campaign activity.
Reciprocate's database now includes 110 charity clients with 28m supporters. Clients are able to swap supporter data to boost their own list of potential donors.
Ian Campbell, head of individual giving at the National Autistic Society, said: "At times when people are thinking twice about which charities they support, it is crucial that we can identify and then speak to those most likely to support us with a regular gift.
"Our work with Reciprocate will empower us with insight beyond that provided by our own database to ensure we can best serve the two million people whose lives are touched by this invisible disability.
The first wave of activity the NAS has planned for this month includes targeted doordrops, reciprocals and cold lists to significantly grow its donor base.
Scott Logie, strategy director at Occam, said: "Reciprocate really is a 'no brainer' for charities such as NAS. With online channels still not yielding the desired level of supporters, direct mail cannot be overlooked.
"Reciprocate provides a response rate of up to 19%, which is almost the same as the response charities get from existing-donor campaigns. Compare that with the average 1.5% response on traditional cold campaigns and the benefits are clear."