Gregorczyk-Abram received 233 votes in the lower house of parliament, while rival candidate Adam Borowski, backed by the opposition Law and Justice (PiS) party, won 177 votes.
Twenty-three lawmakers rejected both candidates.
Her appointment still requires approval from the upper house before she can take office.
Gregorczyk-Abram is a lawyer specializing in human rights and has been involved in legal advocacy and civil rights initiatives.
The current ombudsman, Marcin Wiącek, is due to end his five-year term on July 23.
(pu/gs)
Source: PAP