Learners' satisfaction and persistence are considered critical success factors in online universities where all of the teaching and learning activities are carried out online. This study aims to investigate the structural relationships among perceived level of presence, perceived usefulness and ease of use of the online learning tools, learner satisfaction and persistence in an online university located in South Korea. The specific predictors were teaching presence, social presence, cognitive presence, and perceived usefulness and ease of use. Structural equation modeling (SEM) was used to provide cause-and-effect inferences. The study participants were 709 learners who enrolled in a Korean online university in 2009 and responded to online surveys. The results indicated that teaching presence, cognitive presence, and perceived usefulness and ease of use were significant predictors of learner satisfaction, which was found to be a significant mediator of predictors and persistence. The findings provided substantial implications for designing and implementing teaching and learning strategies in online university environments. (Contains 6 tables and 5 figures.)