The contract with Hub North Scotland involves the delivery of new community hospitals for Badenoch & Strathspey and Skye, Lochalsh & South West Ross.
The agreement follows Scottish government approval of the full business case and planning approval for both projects.
A turf cutting ceremony has already taken place to mark the start of work in Aviemore on the Badenoch & Strathspey facility and work is expected to begin later this summer at Broadford on the Skye development.
The main contractor for both sites is Balfour Beatty and the hospitals have been designed by architects Oberlanders and Rural Design. The mechanical, electrical and plumbing contractor will be Rybka and the civil and structural engineer is Waterman.