Abstract: Macrocephaly-Cutis Marmorata Telangiectatica Congenita (M-CMTC) is a rare syndrome that was first delineated as distinct from Cutis Marmorata Telangiectatica Congenita (CMTC) in 1997. Since that time, there have been over 75 cases reported in the literature, though few are in the dermatology literature. The syndrome is characterized by macrocephaly, neonatal hypotonia, developmental delay, segmental overgrowth, syndactyly, asymmetry, connective tissue defects, and vascular stains. We report three new patients seen at the University of Miami Genodermatoses Clinic with features of M-CMTC. We believe the skin findings in our patients and in the previously published cases of M-CMTC are more consistent with capillary malformations rather than true CMTC. Therefore, we agree with recent publications that this condition be renamed Macrocephaly-Capillary Malformation (M-CM). The differential diagnoses for patients with M-CMTC include Klippel Trenaunay Syndrome (KTS) and Proteus or Proteus-like syndromes. Given the significant prognostic and likely genetic differences among these conditions it is important to distinguish M-CMTC from these syndromes.