Police in Aigio, in the Peloponnese, were on Thursday investigating the circumstances that led to a newborn infant being abandoned in a dumpster.
The dead baby was found by a resident who reported it to police.
The authorities subsequently discovered that a 30-year-old woman had been admitted to a hospital in nearby Rio on Wednesday night with heavy genital bleeding.
The doctors who examined her deemed that she had given birth prematurely but there was no sign of an infant.
Police questioned the woman who denied that the baby found in the dumpster was hers.
An autopsy was to determine whether the baby was hers and the cause of its death.