Belle Wheelan, president of the Commission on Colleges of the Southern Association of Colleges and Schools, cited the private liberal arts school's debt and a lack of funding, planning, assessment and student learning outcomes in the accreditation decision.
Colleges can't award diplomas without accreditation in Texas and an unaccredited school's students can't receive federal or state financial aid.
School President Michael J. Sorrell said in a statement that the school was disappointed with the ruling and will appeal.
Paul Quinn College enrolls about 440 students, boasts of being the oldest historically black school in Texas and was on probation.
Sorrell took the helm of the school in 2007 and immediately worked to change its image. He implemented a business-casual dress code for students, made class attendance mandatory and even cut the Tigers' football program, a move that saved $600,000 a year.
Problems existed before Sorrell's arrival though with building in disrepair, enrollment down and an endowment that had shrunk to less than $5 million.
"We feel strongly about the progress we have made during the last two years," Sorrell said in the statement. "And we are optimistic about our chances on appeal."
Wheelan said in Thursday editions of The Dallas Morning News that Sorrell has made great strides but it was not enough.