The ballots, sent to 5830 voting members of the Academy of Motion Picture Arts and Sciences, list nominees in 19 categories for the Oscars, which will be announced on February 25.
The ballots must be returned to auditing firm Pricewaterhouse-Coopers by 5pm on February 20.
Ballots received after the deadline will not be counted.
Ballots for best documentary feature, documentary short subject, foreign language film, animated short film and live action short film, will be mailed after members have verified their attendance at mandatory screenings, the Academy said in a statement.