The deal is set to generate $200 million (€157m) of cost and revenue-related synergies in three years with 2007 synergies estimated to be at least $75m.
Industry analysts commented that the merger reflected broader changes in the industry, as customers seek to control costs by using suppliers able to provide their research scientists with a fully integrated range of lab services.
Indeed, the merger continues a trend already seen in smaller previous acquisitions by both companies expanding their footprints over the past few years.
Under the terms of the agreement, in which the new company will be named Thermo Fisher Scientific, Fisher's shareholders are to receive one share in the combined company for every two shares, which represented a 7 per cent premium against Friday's closing share price of $73.73
Thermo's shares were 2.3 per cent lower at the close on Monday, down 91 cents at $38.54. Fisher's shares rose 3 per cent to end the session at $75.95.
"This combination brings together two industry leaders in the life, laboratory and health sciences marketplace to create a company that has the product breadth," said Marijn Dekkers, president and chief executive officer of >Thermo.
"By combining our companies' world-class product and service offerings with Fisher's customer access, we expect to accelerate growth by further penetrating our vast customer base," he added.
The deal is expected to adjust 2007's earnings per share of the combined company to be in the range of $2.27 to $2.37, reflecting accretion of approximately 18 per cent to Thermo's consensus 2007 adjusted EPS.
"This is a great transaction that provides Fisher shareholders with enhanced value both today and over the long-term," added Meister.
"By leveraging the operating expertise at both companies, we anticipate realizing the strategic and financial benefits of this transaction quickly."
Thermo Fisher Scientific will become the biggest player in a sector made up of smaller companies and analysts have speculated that this may make it a target for an acquisition by medical-equipment manufacturers such as General Electric or Siemens AG, which have a limited presence in laboratory equipment.
Both companies themselves have consistently added to their stable, ensuring that they have interests in all aspects of the most strategically important markets.
As recently as this year Fisher acquired Clintrak Pharmaceutical for $125m and Athena Diagnostics for $283m, while last year Thermo acquired Kendro Laboratories for $834m.
Thermo Fisher Scientific now compete against such companies such as Applied Biosystems, Beckman Coulter, and Invitrogen.
Thermo had $2.63 billion in sales last year, compared with Fisher's $5.58 billion. The combined company is expected to have $9 billion in sales next year with 30,000 employees.