The Hartford Courant, a daily newspaper with a circulation of 200,000 owned by the Tribune Company, made the admission in a 1,500-word article that ran on the paper's front page on July 4.
The story, "A Courant Complicity, An Old Wrong," written by Jesse Leavenworth and Kevin Canfield, describes the Courant's slave ads and the historical setting in which they were published.
"From its founding in 1764 well into the 19th century, The Courant ran many ads for the sale and capture of human beings," the article reads, but adds, "Slavery was so woven into the nation's economy and social fabric that such ads were probably less controversial than gun or tobacco marketing would be today."
According to the article, slavery was legal in Connecticut, a state with more blacks than any other New England state in the late 1700s, from 1640 until 1848.
"They were used primarily as domestic servants and farmhands," the article read. "The black slaves in this region, for the most part, did not face the dawn-to-dusk, stooping labor and intense abuse suffered by their counterparts in the mid-Atlantic and Southern states."
The article says the paper ran ads for slaveswhich "described scars, brandings and amputations" or listed rewards from one penny to five dollars for the capture of runaway slavesuntil at least 1823.
"Unfortunately, the practice of advertising for slaves was commonplace in newspapers prior to abolition," said Ken DeLisa, a spokesman for The Courant quoted in the article. "We are not proud of that part of our history and apologize for any involvement by our predecessors at The Courant in the terrible practice of buying and selling human beings that took place in previous centuries."
In recent years, several companies in the United States have, sometimes reluctantly and under pressure from historians or rights groups, admitted their role in the slave trade.
In March of this year, another Hartford company, Aetna Insurance, expressed its " deep regret" for possibly insuring the lives of slaves as late as 1853.
Aetna also concluded that "beyond our apology, no further actions are required, considering our strong, consistent commitment to diversity over many years and the numerous philanthropic and workplace diversity initiatives we undertake and for which we have been publicly recognized."
The issue of businesses' complicity in the slave trade has also surfaced in discussions of possible reparations to descendants of slaves. The Chicago city council passed a resoution calling for Congress to examine the issue in May. The Michigan state assembly has considered a similar bill. Florida has paid reparations to descendents of victims of a 1923 race riot.
Rep. John Coyners, D-Mich., has for eleven years introduced a bill calling for a commission to study reparations.
A similar effort is underway in Europe, where Swiss banks and the German government have begun to address their financial obligations to Holocaust survivors and their descendents.
The German parliament Thursday offered a formal apology to Nazi-era slave and forced laborers, passing a bill setting up a $5 billion compensation fund that should begin making payments to aging victims this year.
Companies that have pledged their participation in the fund include some of the biggest in world business, including DaimlerChrysler, Deutsche Bank, Siemens and Volkswagen.
By JARRETT MURPHY