A further 20 posts are going at CMS although some of those people are employed through outsourcing suppliers Integreon, Initial and Xerox.
It is thought CMS's relationship with Integreon will continue with that company now likely to supply staff into Scotland as well.
A spokeswoman for CMS UK said: "There has been considerable work going on as we prepare for the combination of CMS with Dundas & Wilson.
"With any combination it is regrettably to be expected that there are some duplication of roles resulting in redundancy.
"While there is no reduction in the number of lawyers, we can confirm that as we anticipated about 60 support roles have been made redundant with two thirds of those roles within Dundas & Wilson and one third within CMS and its third party suppliers."
The firms did not say how many posts were being cut in Scotland. D&W has a paralegal unit in its Glasgow office which processed routine legal services as a way to cut costs for clients.
The merger will see all legal and support staff at D&W in London and Aberdeen leave their offices to move to CMW premises in each city.
The D&W sites in Edinburgh and Glasgow are likely to retain the name of the firm, one of the oldest and largest in Scotland, for a transitional period before being rebranded as CMS.
A number of D&W partners have departed in recent months including former chairman David Hardie, health and safety head Mark Brumwell, employment specialist Mandy Laurie, real estate disputes boss Andrew Walker and experienced banking lawyer Allan Wardhaugh.
CMS recently promoted 31 partners across Europe including 11 in the UK. Real estate lawyer Margaret McLean, who is based in Edinburgh, was the only D&W person to make the step up.
The combined firm will have more than 830 partners and 5,600 employees operating in 57 offices across 31 countries.
Separately BTO has completed the transfer of the private client team from DAC Beachcroft Scotland.
Partner Neil Headrick and associate Cameron Urquhart as well as some support staff will join BTO's Glasgow office.
DAC, which moved into Scotland through merger with Andersons in 2012, said the agreement will ensure a smooth transition for clients and allow it to focus on work in the commercial and insurance sectors.