Organizers said more than 1,000 people marched through downtown Atlanta to support Troy Davis.
Davis is set to be executed Wednesday for the killing of an off-duty Savannah police officer.
Amnesty International and the NAACP organized the march and rally Friday through Atlanta to Ebenezer Baptist Church.
Davis’s supporters say Georgia is set to put an innocent man to death, citing eyewitnesses who claim another man killed Officer Mark MacPhail in 1989. MacPhail was shot while off duty and rushing to help a homeless man being attacked.
Prosecutors say there's no doubt they charged the right person with the crime, and courts have repeatedly upheld his conviction.
Some marchers chanted, "Legal lynching's got to go" and sang spirituals.
Meanwhile, a Savannah church will hold a prayer service for Davis Saturday evening.
Family and supporters planned to gather for the service at St. Philip Monumental AME Church.
Davis insists he's innocent and has avoided execution three times since 2007. A federal judge ruled last year that Davis didn't have enough evidence to clear his name, despite claims his lawyers had made for years.
Advocates are urging Georgia's pardons board to grant Davis clemency. The board will meet Monday to consider the case.