The Grade II-listed building dates back to the 1930s and provides meeting facilities and 50 en-suite rooms. The application included plans to revamp and upgrade the facility's Astel House, Sunken Lounge, Stephenson Restaurant, lecture theatre, Wyvern Bar, Business Centre, reception and toilet facilities.
Bondholder Derby Conference Centre said the decision to carry out the work was commercial and would provide rentable space.
The Derby Conference Centre originally opened its doors as a training college for railway staff in 1938 and was designed by William H Hamlyn, London Midland and Scottish Railway's Principal Architect. The construction originally cost just £50,000.