The impact of malpractice concerns on pathologists' use of defensive medicine and interpretations of melanocytic skin lesions (MSLs) is unknown.A total of 207 pathologists interpreting MSLs responded to a survey about past involvement in malpractice litigation, influence of malpractice concerns on diagnosis, and use of assurance behaviors (defensive medicine) to alleviate malpractice concerns. Assurance behaviors included requesting second opinions, additional slides, additional sampling, and ordering specialized tests.Of the pathologists, 27.5% reported that malpractice concerns influenced them toward a more severe MSL diagnosis. Nearly all (95.2%) pathologists reported practicing at least one assurance behavior due to malpractice concerns, and this practice was associated with being influenced toward a more severe MSL diagnosis (odds ratio, 2.72; 95% confidence interval, 1.41-5.26).One of four US skin pathologists upgrade MSL diagnosis due to malpractice concerns, and nearly all practice assurance behaviors. Assurance behaviors are associated with rendering a more severe MSL diagnosis.