The 2005 Tirreno–Adriatico was the 40th edition of the Paris–Nice cycle race and was held from 9 March to 15 March 2005.

The race started in Civitavecchia and finished in San Benedetto del Tronto.

The race was won by the then-current road race world champion Óscar Freire of Rabobank.

Twenty-three teams, containing a total of 184 riders, participated in the race:[2]