A district court in Warsaw found the man, named only as “Kajetan P.” guilty of murdering the 30-year-old victim in February 2016.
The killer, dubbed “Hannibal” by the Polish media, attacked the woman in her Warsaw apartment and dismembered her body, state news agency PAP reported.
After the gruesome crime he fled the country, sparking an international police hunt, and was eventually tracked down in Malta.
According to Polish media, the man told investigators that the murder was designed to “eliminate a weakness,” namely “the belief that human life is worth more than a pig or a mosquito.”
He reportedly told prosecutors that he had been trying to purge himself of flaws, and that he had embarked on a programme of what he described as “perfecting himself,” both physically and intellectually.
The man’s defence lawyers said they would appeal against Tuesday’s verdict.