Edmonton Police say the number of sexual assaults in 2011 was up 14 per cent over the previous year.
There were 687 reported incidents in 2011, compared to about 600 in 2010.
Karen Smith with Sexual Assault Centre of Edmonton sees at least two reasons for the increase.
"The access to drugs and alcohol that young people have. When young people are under the influence of intoxicants, they seem to commit more sexual assaults," she said.
"The other thing is that more and more people are coming forward to say, 'Hey, this happened to me and wasn't right.'"
Smith believes raves or all-night dance parties are a factor. On a typical weekend, the Sexual Assault Centre gets 15 calls. That number jumps to 40 whenever a rave takes place, Smith said.
"And all of those people saying they were assaulted after the rave or during the rave," she said.
In his year-end interview with CBC News, Police Chief Rod Knecht called the increase a big concern.
"We're going to have to continue to focus on that and try to drive that number down because the victimization is tremendous for people," he said.
In November 2010, Edmonton Police and the Sexual Assault Centre of Edmonton launched the "Don't be that Guy" campaign, aimed at discouraging young men from taking advantage of women who've been drinking.
A similar campaign is planned for the end of 2012 to keep a spotlight on the issue.