James Naughtie hosts the traditional celebration live from London's Royal Albert Hall, with Andrew Davis conducting the BBC Symphony Orchestra.
Pieces by Rossini, Mozart and Rachmaninov are among the highlights, plus the European premiere of Variations for Orchestra by British composer Hugh Wood.
There is also a visit to the Proms in the Park concert taking place simultaneously in Hyde Park and hosted by Terry Wogan.
Coverage continues at 9pm on BBC1. The Albert Hall Prom can also be heard on Radio 3.
See today's choices.
(See Brian Kay: page 40; BBC Proms 98 Double CD offer: p128)