After its more famous cousin, the twelve bar blues, the sixteen bar blues is the next most common blues form. A sixteen bar blues consists of four lines of four chords each. Usually, the first two lines of four chords consist of some combination of the I and IV chords with the last four chords comprising a turnaround, while in the third set of four chords there is typically a chord change between all four bars. A typical sixteen bar blues progression might be:
I, IV, I, I,
IV, IV, I, I,
IV, V, I, IV,
I, V, I, V7

The sixteen bar form is commonly associated with "eastern blues" such as Appalachian blues, Georgia blues, and Carolina Blues, although it is actually quite common in the more well known Mississipi and Texas blues traditions. Some well known sixteen bar blues include Muddy Waters' "Hoochie Coochie Man", Jesse Fuller's "San Francisco Bay Blues", Robert Johnson's "Last Fair Deal Gone Down", and the trucker anthem "Six Days on the Road".