"We are thankful to God that three more hostages were released last night. Those who were released are safe and seem to be in good spirits," Ohio-based Christian Aid Ministries said in a statement.
US State Department spokesman Ned Price on Monday confirmed the release, adding that the United States is continuing to work to secure the release of the others.
Haitian National Police spokesman Garry Desrosiers said the three were released on Sunday night. He declined to give additional details, citing the security of the remaining hostages.
Sixteen Americans and one Canadian, including five children, were abducted after visiting an orphanage. The incident has highlighted Haiti's dire kidnapping problem, which has worsened in recent months amid economic troubles and political upheaval.
Two other ministry group members were released last month.