Joe Dolan and his family live along Greenwich Street.
His 15-year-old son, Dominic, has Cerebral Palsy, which makes it difficult to walk on his own.
Dolan says the ramps were taken between noon and 3 p.m. Thursday.
He believes that those responsible took the ramps for scrap metal in order to sell them for drugs.
Dolan has filed a police report in the theft of the ramps.