PURPOSE OF REVIEW: The purpose of this review is to summarize the recent (past 5 years) available evidence regarding the association between plant-based diets on cancer risk from clinical trials and observational studies. Biological mechanisms and gaps in the current literature will also be discussed. RECENT FINDINGS: There is a lack of intervention studies but there are abundant observational studies assessing the association between plant-based diets and cancer risk, including multiple longitudinal cohort studies and similar data from case-control studies that demonstrate a decreased overall cancer risk with plant-based diets. Case-control studies support a decreased risk of colorectal and breast cancers with plant-based diets, but results for specific cancers remain inconsistent in cohort studies. Current evidence from observational studies indicates an inverse association between plant-based diets and overall cancer risk. Future research should include intervention studies, address inconsistencies in dietary assessment methods and provide greater detail on underrepresented groups.