Electoral officials said results of the November 6 election showed Rakhmonov, who has been in office since 1992, receiving more than 76 percent of the vote -- well over the 50 percent needed for victory.
Some leading opposition parties boycotted the election, saying it was not democratic.
Reports quoted Western observers as raising a number of concerns about the fairness of the election. Monitors from the Organization for Security and Cooperation in Europe (OSCE) are due to give their assessment of the vote later today.
The nearest challenger to Rakhmonov was Olimzhon Boboyev of the Economic Reform party, who officials said received about 7 percent.
Officials put voter turnout at more than 90 percent.
(compiled from agency reports)
Tajikistan's Presidential Election
Imomali Rakhmonov has ruled Tajikistan since 1992 (epa file photo)
A THIRD TERM? On November 6, Tajikistan will hold its first presidential election since 1999. Incumbent President Imomali Rakhmonov is seeking a third term under controversial constitutional amendments adopted in 2003. The opposition has accused Rakhmonov's administration of using dirty tricks and legal pressure to split and weaken opposition parties. Most observers believe the November ballot will be less competitive than the 1999 election.