Medical students in problem based learning (PBL) are prone to burnout yet since the teaching approach was introduced in a College of Health Sciences in Kenya, no investigations on this risk has been done. The purpose of this study was to determine the prevalence of burnout ,the main, mediating and moderating effects of coping styles on the associations between learning environment and burnout.One hundred and eighty two (182) Students distributed across years 2,4,and 6 of study in a College of Health Sciences in a University in Eldoret, Kenya responded to 3 self report scales on learning environment,coping and burnout.Percentages were computed and hierarchical multiple regression analysis ran on the data using SPSS 17.Results showed 83.4% of students suffered moderate to high burnout.Coping styles had main and mediating but no moderating effects on the environment-burnout associations.Ineffective coping worsened student-burnout. Poor learning environment worsened burnout in students through the ineffective coping styles they adopted.It is suggested that learning environment be improved and students be coached on effective coping, and prevention and management of burnout.