In the current political environment, the plight of undocumented immigrants in the United States (U.S.) remains perilous and uncertain, and this precarious situation is magnified for undocumented immigrants with end-stage renal disease (ESRD). For this population, access to hemodialysis varies dramatically from standard-of-care thrice-weekly hemodialysis, to the other extreme of emergency-only hemodialysis which is the practice of offering hemodialysis only after a patient meets "critically ill criteria." Due to the exclusion from Medicare, undocumented immigrants are not included in the United States Renal Data System (USRDS), and therefore the prevalence of undocumented immigrants with ESRD in the U.S. remains unknown. In this review, we assemble the published literature, press reports, and other data sources to arrive at an estimated crude prevalence of undocumented immigrants with ESRD. In 2015, USRDS data reported an adjusted ESRD prevalence of 2,988 per million population (PMP) among documented U.S. Hispanics and 1,902 PMP among documented U.S. non-Hispanics, adjusted for age, sex, and race. Although 77.8% of undocumented immigrants in the U.S. are from Latin America, simply applying USRDS-adjusted prevalence estimates for U.S. Hispanics with Medicare to undocumented immigrants would likely overestimate the undocumented immigrant population with ESRD given the younger age of the immigrant population. Applying the estimates from the states with the largest population of undocumented immigrants, the range for California and Texas is 500 - 798 PMP which results in an estimate of 5,500 - 8,857 undocumented immigrants with ESRD living in the U.S.