This systematic review examines the evidence of implicit biases among healthcare professionals towards patients. The review searched multiple databases for peer-reviewed articles published between March 1, 2003, and March 31, 2013. Two reviewers assessed the eligibility of the identified papers based on precise content and quality criteria. The results identified 42 eligible articles, 17 of which used implicit measures ( Implicit Association Test in 15 and subliminal priming in 2) to test the biases of healthcare professionals. Twenty-five articles employed a between-subjects design using vignettes to examine the influence of patient characteristics on healthcare professionals' attitudes, diagnoses, and treatment decisions. The most common biases examined were racial/ethnic and gender biases, but ten other biases were also investigated. The review found evidence of implicit bias in healthcare professionals, with a significant positive relationship between levels of implicit bias and lower quality of care. The discussion highlights the need for the healthcare profession to address implicit biases in disparities in healthcare and calls for more research in actual care settings and a greater homogeneity in methods used to test implicit biases in healthcare.This systematic review examines the evidence of implicit biases among healthcare professionals towards patients. The review searched multiple databases for peer-reviewed articles published between March 1, 2003, and March 31, 2013. Two reviewers assessed the eligibility of the identified papers based on precise content and quality criteria. The results identified 42 eligible articles, 17 of which used implicit measures ( Implicit Association Test in 15 and subliminal priming in 2) to test the biases of healthcare professionals. Twenty-five articles employed a between-subjects design using vignettes to examine the influence of patient characteristics on healthcare professionals' attitudes, diagnoses, and treatment decisions. The most common biases examined were racial/ethnic and gender biases, but ten other biases were also investigated. The review found evidence of implicit bias in healthcare professionals, with a significant positive relationship between levels of implicit bias and lower quality of care. The discussion highlights the need for the healthcare profession to address implicit biases in disparities in healthcare and calls for more research in actual care settings and a greater homogeneity in methods used to test implicit biases in healthcare.