Regular skin self-examination (SSE) reduces melanoma mortality but is not often conducted. To promote SSE performance in individuals at increased risk for melanoma. One hundred sixteen individuals at heightened risk for development of melanoma (i.e., personal/family history of melanoma, high-risk mole phenotype) who did not conduct a thorough SSE during in the prior 3 months were randomly assigned to receive either an automated internet-based intervention (mySmartCheck) or usual care (UC). One hundred sixteen participants completed surveys before random assignment and 99 completed the follow-up survey 13-weeks afterward. The primary outcome was participant self-reported examination (SSE) of all 15 parts of the body in the last 3 months. Secondary outcomes were SSE of any part of the body in the last 3 months and number of body parts examined during the last SSE. More mySmartCheck participants examined all 15 body parts (32.6% vs. 7.1%, p = .001). More individuals in mySmartCheck reported conducting SSE on any body part than those in UC (81.4% vs. 62.5%, p = .04). Effect sizes were large (d = 1.19 all 15 body parts) to moderate (d = 0.55 for any body part). mySmartCheck participants examined more body areas than UC participants (12.7 vs. 10.3, p = 0.003) during the last SSE. Participants in mySmartCheck reported higher levels of knowledge of suspicious lesions, SSE benefits, SSE self-efficacy, and planning for SSE, and lower SSE barriers, than those assigned to UC. mySmartCheck had a significant positive impact on SSE performance and behaviors. Additional research with a larger sample size, a longer follow-up, and more varied clinical settings is needed. ClinicalTrials.gov registration # NCT03725449 (https://clinicaltrials.gov/ct2/show/NCT03725449).