This is a study of the relationship between EAS temperament traits, age and gender, and religious fundamentalism in an adult Polish sample. Participants were sampled from among people who tended towards secularisation. A total of 902 participants, including 551 women and 351 men, aged 18 to 58 (M=27.73; SD=7.40) were studied. Participants were students in a variety of university faculties and adults with higher education representing a variety of professions. They all lived in the Warsaw area. Temperament was assessed with Buss and Plomin's EAS Temperament Survey. Religious fundamentalism was assessed using Altemeyer and Hunsberger's Religious Fundamentalism Scale (short, revised version). The level of religious fundamentalism was found to be associated with the temperament traits of sociability and anger. All three variables decrease in intensity with age. Women have higher levels of religious fundamentalism than men.