Monserrate, who was convicted of misdemeanor assault charges in October for "unintentionally injuring girlfriend Karla Giraldo while dragging her through his apartment lobby," has been a target of the gay community since he voted against gay marriage earlier this month. The Queens lawmaker initially voiced his support for the bill.
Members of the LGBT activist group The Power disrupted the Queens party with anti-Monserrate cries referencing his assault trial and his broken promises to the LGBT community.
One activist screamed out, "It's the one-year anniversary of Hiram slashing his girlfriend! Hiram's a wife beater! He can get married and we can't!"
A video released by the activist group shows the protesters being ushered out of the building and confronting Monserrate's openly gay chief of staff Wayne Mahlke.