The person elected to the £85,000-a-year post will be responsible for setting the force's budget of about £400m, outlining its priorities and hiring and firing the chief constable.
More than 50 polling stations across Bracknell Forest and 76 in Wokingham borough will be open from 7am-10pm today (Thursday, November 15).
Bracknell Forest Council leader Cllr Paul Bettison said: "This is an important role, it's going to be a role that influences policing and potentially impacts upon our daily lives. After all, most people when I knock on their doors say they care about local crime figures.
"There's no point in saying that's of interest if you don't go out and vote!"
Residents living in the Town Centre ward of Bracknell will also be able to cast their vote for a new town councillor, following the resignation of Neil Ellis, landlord of The Bull pub in High Street, last month.
Polling for the by-election will take place at K2, the Kerith Centre, in Church Road, between 7am-10pm today (Thursday).
A total of 69 polling stations across Royal Borough will be open from 7am-10pm.
In Ascot people can go to All Saints Church Hall, in London Road to cast their vote, as well as Ascot Library in High Street and Cheapside Village Hall.
In Sunningdale there are also polling stations at Sunningdale Village Hall, Church Road, at a mobile unit in Waitrose car park, London Road.
South Ascot Church Hall in Church Road is also a polling station, as is Ascot District Day Centre in Sunninghill
For a full list of the six PCC candidates look here: http://www.bracknellnews.co.uk/news/roundup/articles/2012/10/31/63976-pcc-candidates-go-under-the-microscope/