The charity said more needed to be done to allow women access to justice
The number of people convicted of rape in Scotland has dropped to a 25-year low, according to new statistics.
Figures obtained by Rape Crisis Scotland from the Scottish government show that just 25 of the 821 rapes reported in 2008/09 were proven.
The charity said this was the lowest number since 1984.
A National Sexual Crimes Unit was established last May to lead the prosecution of the most serious sexual offences.
It contains some of the country's most experienced legal experts and undertakes cases involving rape, sexual abuse, images of child abuse, sexually motivated murder and people trafficking for sexual exploitation.
Sandy Brindley, national co-ordinator of Rape Crisis Scotland, said the fact that only 83 people faced rape charges in court in 2008/09 showed that more still needed to be done to improve justice for victims.
She added: "All these changes are welcome and it is likely that it will take some time for these to have a real effect.
"However, the new figures from the Scottish government give real cause for concern.
"It is clear that much remains to be done if women in Scotland are to be able to access justice following a rape."
She said more work was needed to change public attitudes towards rape victims, as many people still believe it is the victim's fault.
Ms Brindley also suggested looking at whether rape victims should have their own dedicated lawyer, as happens in many other countries.
A Crown Office spokesman said: "These statistics do not reflect the most recent developments in the ongoing commitment to improve the prosecution of sexual offences.
"In 2006, the Lord Advocate launched a review of sexual offences which resulted in 50 recommendations to improve the prosecution of rape and other sexual crimes.
"Since then there has been much work to implement these, including a comprehensive specialist training programme for all staff."
He added: "It should be noted that in cases where the accused is prosecuted for a course of conduct involving multiple rapes, this will be libelled as a single charge.
"In a case where rape is not the main charge, this will not be reflected in the figures.
"For example, in the case of Marek Harcar, who was convicted of the rape and murder of Moira Jones, this would not be recorded as a rape conviction."