The new reward being offered is $10,000 for the discovery of Mark Himebaugh and $25,000 if it leads to his safe return.
As was the case back then, his mother Maureen, now 60, hopes her son will come home.
"I want Mark to know that I'm still standing and I'm going to be here for him when he comes home," Maureen Himebaugh said.
Maureen's home in Del Haven looks very much like it did the day Mark disappeared.
As does the nearby beach where Mark's sneaker was found and the park where police know he was seen.
Back in '91, firefighters and others searched in vain.
In the years that followed, detectives ran down hundreds of leads taking them miles from South Jersey.
If Mark is alive, it's thought the little boy might look like the drawing in the picture above.
The sheriff's office has set up an anonymous tip system for calls and texts, which you can reach here.
Maureen is buoyed by a California case where an 11-year-old kidnapped girl was found 18 years later.
"He may have been taken by someone because he was so adorable and raised and someone knows something," Maureen said.
Maureen hopes, after all these years, there is someone who can help.
She also hopes that this new reward money will move them to tell investigators that bit of information that could unlock this 20 year old mystery.
To submit a tip in this case, go to http://www.cmcsheriff.net/ and click on "Anonymous Web Tip" on the left.