The incumbent on the account is AKA Media.
The appointment follows a pitch process that launched in December last year after eHarmony received interest from a number of undisclosed media agencies.
According to Nielsen, eHarmony spent US$7.2 million on main media in the year to November 2010, up from US$2.9 million in the prior period. OMD said the business is worth US$10 million in billings.
Jason Chuck, Australian country manager at eHarmony, said, "We're really excited to be working with OMD who demonstrated a great balance between forensic DR techniques and strategic insights that can help take our brand to the next level."
The online dating site eHarmony.com.au launched in Australia in 2007, using a scientific Compatibility Matching System to help Australian singles find love.