A "postcode lottery" is also said to exist across Scotland's police forces
Fewer than 10% of rape cases reported to the police make it to court, figures released by the Scottish Liberal Democrats have shown.
A total of 908 cases of rape were recorded in Scotland in 2007/08, yet just 88 were pursued in court.
Lib Dem justice spokesman Robert Brown said the figures were "very concerning" and that prosecution levels must rise.
The Scottish Government said it was working to improve the justice system's response to rape.
The figures also revealed a "postcode lottery" across Scotland's eight police force areas and the Scottish Government was urged to improve support for rape victims.
The statistics ranged from a high of 14.3% of cases proceeded against in the Northern Constabulary to a low of 3.6% in Tayside.
Mr Brown, who obtained the figures, said: "These figures are very concerning. It is obvious that much more needs to be done to improve the prosecution levels for cases of rape in Scotland."
He added: "It is not the place of politicians to interfere with the legal process, which must continue to allow a fair trial to people accused of rape.
Mr Brown called for more support to be offered to rape victims
"But the government must make sure that victims of any rape can have confidence that their case will be taken seriously, they will be treated with sympathy, and everything possible will be done to bring justified and provable cases to court."
The Glasgow region MSP also said the "postcode lottery across Scotland's police boards is also very worrying".
He said those police boards with low rates of rape cases proceeding to court must learn from other areas.
Mr Brown added: "Rape is a serious crime. Boosting the number of cases proceeding to court would send a strong message that rape is unacceptable and that offenders will face the full force of the law."
A Scottish Government spokesman said: "Rape is a horrific crime, and we are working with all relevant agencies to continue to improve the justice system's response to such vile offences - from intensive investigation of reported crime to supporting victims and punishing offenders.
"Ensuring that the law is clear, robust and reflects the standards of modern society is a key element of - indeed the foundation for - this ongoing work."
The spokesman said the official figures showed the number of recorded rapes had fallen in each of the past two years while the number of cases proceeded against rose in the past year.
He also said the Sexual Offences Bill, passed unanimously by the Scottish Parliament in June, "provides for the first time in Scots law a statutory definition of rape, making clear to lawyers and members of the public alike what is lawful and what is not".