The body of 34-year-old Jennifer Tong was found on June 26, 1993 in the back seat of her car on Spring Mill Road in Villanova, on Philadelphia's Main Line.
The discovery came hours after police say she was taken from her home in the Lawrence Park section of Broomall, Delaware County.
Tong had been shot once in the head.
Her killer has never been found.
Radnor Police Superintendent William Colarulo said police decided to re-open the case in light of new advances in DNA and fingerprinting technology.
He said the department has re-submitted fingerprint and DNA evidence for analysis, and that detectives have started re-interviewing surviving witnesses.
Radnor Police Sergeant Joseph Maguire, a 33-year veteran of the department and the detective originally assigned to case, is heading up the investigation.
Police say they have been looking at several persons of interest in the case, but declined to name them.
The Citizens Crime Commission is administering a $10,000 reward for information leading to an arrest or conviction.
Colarulo urged anyone with information related to the case to contact the commission at 215-546-TIPS.