Children were raped by multiple perpetrators, abducted, trafficked from other cities in the UK to Rotherham, it said.
Some Asians of Pakistani origin were also involved the report said.
The report said: "By far the majority of perpetrators were described as 'Asian' by victims."
The report, commissioned by Rotherham Borough Council, revealed there had been three previous inquiries.
Council leader Roger Stone said he would step down with immediate effect.
Stone, who has been the leader since 2003, said: "I believe it is only right that as leader I take responsibility for the historic failings described so clearly."
"Several staff described their nervousness about identifying the ethnic origins of perpetrators for fear of being thought as racist," Alexis Jay said, a former chief social work advisor to Scottish government.
The inquiry team noted fears among council staff of being labelled "racist" if they focused on victims' description of the majority of abusers as "Asian" men.
Jay, who wrote the latest report, said there had been "blatant" collective failures by the council's leadership, senior managers had "underplayed" the scale of the problem and South Yorkshire Police had failed to prioritise the issue.
Jay said: "No-one knows the true scale of child sexual exploitation in Rotherham over the years. Our conservative estimate is that approximately 1,400 children were sexually exploited over the full inquiry period, from 1997 to 2013."
Revealing details of the inquiry's findings, Jay said: "It is hard to describe the appalling nature of the abuse that child victims suffered."
The inquiry team found examples of "children who had been doused in petrol and threatened with being set alight, threatened with guns, made to witness brutally violent rapes and threatened they would be next if they told anyone".