The new lewd correspondence was posted Monday by the gossip website The Dirty. The woman involved was not identified.
Weiner resigned from Congress in June 2011 after acknowledging having sexual conversations with at least a half-dozen women.
The woman says her online relationship with Weiner lasted for six months and continued into last summer.
In his statement, Weiner does not address when the newly revealed exchange happened. He does say his behavior created "challenges in our marriage that extended past my resignation."
When he announced his mayoral run two months ago, Weiner said "other texts and photos were likely to come out." He is near the top of most mayoral polls.
More Nation & World Headlines
Four Confederate flags left at MLK center, church in Atlanta Cincy police officer pleads not guilty in fatal shooting Cop indicted for murder in traffic-stop shooting Will ‘Happy Birthday’ song be free to use soon? Debris linked to missing Malaysian 777 Export-Import Bank excluded from highway bill 777 departs Aleutians after emergency landing House approves highway funding bill
Our new comment system is not supported in IE 7. Please upgrade your browser here.