The march was held in response to racial abuse endured by South Belfast MLA, Anna Lo, a signatory of the Prospect Pledge, who also hosted an event for the campaign at Stormont in March.
Racial tensions have also been inflamed recently by controversial remarks made by the First Minister Peter Robinson about Islam.
Prospect members from several employers, including the National Trust and Aspect group, showed their solidarity by attending the rally, which was co-organised by Amnesty International NI and the Northern Ireland Council for Ethnic Minorities.
The march from Writer’s Square to Belfast City Hall was led by Peter Bunting, assistant general secretary of ICTU, Belfast's Lord Mayor, Nichola Mallon, Dr Donald Watts, president of the Irish Council of Churches, and Dr Mazhar M Khan, a leading member of Northern Ireland's Muslim community.
Kasia Garbal, an ICTU migrant workers' project officer who is originally from Poland, said recent hate crimes had "made me wonder why I'm here".
She said: "I've been here for 10 years and this is my home, but the last few weeks have been really difficult.
"It's moving for me that so many people of all nationalities, races and different beliefs came out here today."
Commenting on Prospect’s involvement in the rally, National Trust branch president Paul Stewart said: “As a trade union branch we are appalled by the comments made by Northern Ireland’s first minister and the message sent today to those in power wherever they are in the UK is that we are watching and if needs be we will challenge you at every turn.”