Born as a man, Ms Grodzka, now 57, completed her gender change last year with the help of the Trans-Fuzja organisation focused on gender change.
Topping the Janusz Palikot Movement party list in the devoutly Catholic southern city of Krakow - once home to the late Polish-born pope John Paul II - Ms Grodzka was thrilled by Sunday's strong showing at the polls.
"If I'll be elected in Krakow, I'll be Poland's first transgender woman, and the only transgender MP not only in Poland, but the entire world," she said. "In New Zealand, there was Georgina Beyer, but she is no longer an MP since 2007," Ms Grodzka added.
"I'm a leftist. For years I voted for the SLD (social democrats) until they corresponded to my ideals. But they failed in the area of moral values," she said.
Advocating liberalising Poland's restrictive abortion law, free access to contraception and legalising soft drugs and gay marriage among others, it scored 10.1 per cent in a TSN/OBOP exit poll with a 1.5 per cent margin of error.
