Sisis has become a division of Howardson Ltd, alongside Dennis, from 4 January.
Sisis, based in Macclesfield, Cheshire, is a long-established manufacturer of professional grounds maintenance equipment for natural and artificial surfaces.
Dennis MD Ian Howard said: "We have acquired the respected brand, designs, patents and intellectual property and this new partnership is part of our ongoing investment strategy.
"Our traditional strengths – reliability and excellent customer support – will enhance this partnership and we are optimistic about our future together, working as a team to further grow our profile in the market, our products dovetail extremely well.
"We will now be conducting an immediate review of all aspects of the business, including customer service and supply.
A selection of Dennis and Sisis professional groundscare products will be showcased on stand A4 at BTME in Harrogate on 18-20 January 2011.