Pembury Hospital will boast 512 beds, with the first new facilities planned to open in early 2011 and the project completed by autumn 2012.
An NHS spokesman said the hospital has been designed to maximise infection control, with separate planned and emergency areas to reduce the risk of infection.
It will feature a full range of services, including planned and emergency surgery, orthopaedics, a women and children's centre and outpatient services.
MP for Tunbridge Wells Greg Clark said: "This is a momentous day for everyone in Tunbridge Wells and West Kent.
"The whole community has campaigned for so long for the new Pembury Hospital to be built and after years of frustration and setback, we now have the final go-ahead with building work starting this month.
"It is thrilling that local hospital facilities are at last to be catapulted into the 21st Century."