Relations between epistemic perspective and online epistemic processing of evidence when reading a text were examined. Thirty-seven young adolescents and 24 graduate university students were asked to read and think aloud with two texts, one in the history domain and the other in the science domain. Participants also completed a prior-knowledge test and an instrument assessing their epistemic perspective. Results showed that participants who exhibited an evaluativist epistemic perspective and high prior knowledge used the epistemic standard of scientific research more than participants who held a nonevaluativist epistemic perspective. Furthermore, an age-related developmental difference was observed, with adults using the epistemic standard of scientific research more than young adolescents. Domain differences were observed in both participants' epistemic perspectives and online epistemic processing. Participants overall engaged in online epistemic processing of evidence more in the history topic than in the science topic.