The celebrated tenor, 69, has been the company's artistic director for four years.
In a letter to the opera's board, obtained by The Washington Post, Domingo suggests the company should consider a merger with the nearby Kennedy Center in an effort to stay financially viable.
He writes, ""You can rest assured that I will do everything I can to help during this, my last year as general director.""
WNO President Kenneth Feinberg says, ""He will be missed, but all good things must come to an end.""
Under his current contract, the Spaniard will conduct performances of Madame Butterfly and Don Pasquale in 2011.
Domingo's role as the artistic director of the Los Angeles Opera will not be effected; he recently signed a new contract to remain there until at least 2013.