Introduction: During teaching in web-based learning environments, a new and different environment must be created compared to face-to-face environments. However, the lack of physical presence of teachers and learners in an online learning environment can turn into a major dilemma that can have adverse effects on learners' satisfaction and learning.So the aim of this study was to Investigating the relationship among educational, social and cognitive presences with students' academic performance in e-learning courses..
Methods: The the present research had a descriptive- correlational research design (causal model). The population of this study included all students enrolled in the web-based courses during the academic year 1396-1397 in tehran. a sample of 307 students at the postgraduate level were selected through cluster random sampling and responded to the Arbaugh et al(2008) Community of Inquiry framework survey instrument of which, 271 questionnaires could be analyzed .Data were analyzed using path analysis.
Results: The results showed that the structural model of learner's academic performance in e-learning courses is a valid model and data are fitted with theoretical model (RMSEA = 0.076). Based on this model, 48% of the variance in academic performance can be explained. Therefore, teaching presence on social presence, cognitive presence and academic performance, social presence on cognitive presence and academic performance and cognitive presence on academic performance  have  a  significant direct effect. As a result, these factors can properly explain the academic performance of learners in the web-based courses.
Conclusions: Accordingly, it is possible to improve the academic performance of learners by enhancing presence factors