A total of 5,359 constituencies have been formed and 4.8 million voters are registered to vote, according to the Central Electoral Commission. Along with Aliyev, six other candidates are also competing for the office.
Polling stations across the country opened at 8 a.m. (0300 GMT) and were due to close at 7:00 p.m. (1400 GMT).
Though the opposition has said to boycott the voting, it started quietly when polls opened across the country.
According earlier polls, Aliyev is almost certain to gain a second term, extending his presidency for another five years.
The president, 46, took office in 2003 as president after his father Heydar Aliyev's death.
