Satrudhan and Sangeeta Paswan were arrested for kidnapping the infant from Badarpur in South East Delhi in September.
The arrest came on a complaint filed by one Pawan that Sangeeta had kidnapped their son in September.
He said his wife and Sangeeta went to a market in September along with the infant. After a few minutes, Sangeeta told Pawan's wife that she was going home and that she can take the infant with her.
But when the woman came to her house, she was shocked to see both the infant and Sangeeta missing there.
Police fast-tracked investigation and arrested Sangeeta from Sitamarhi district in Bihar. They also managed to rescue the infant.
Satrudhan surrendered in a police station here on Saturday, they said.
"During their sustained interrogation, the couple disclosed that they had married 10 years ago but had no kids. They had planned to reside as tenant in Badarpur area and kidnap a child. They become familiar with Pawan and his family members," a senior police official said.
Both the accused have been produced before a court in Saket.