The high vulnerability of transgender (TG) persons to HIV infection and the difficulties associated with access to health services can lead to delays in the diagnosis and treatment of HIV infection, thus increasing the risk of transmission of HIV by this population. We performed a retrospective study to analyze the main characteristics of TG living with HIV infection in a hospital in Madrid, Spain and to identify issues related to lack of access to the health care system and combination antiretroviral therapy (cART). We analyzed 28 TG, of whom 22 (78.6%) were TG women. Median age was 28 years (interquartile range [IQR]: 29–45), 24 (85.7%) were Latin American (all of them without health insurance), and 12 (42.8%) were sex workers. Accessibility to the health system was more difficult for 22 (78.6%) of foreign-born TG people living with HIV, with a median delay to initiation of cART of six months (IQR: 2–24). These values were greater than those recorded for the control group comprising other people living with HIV (16.9% and one month, respectively). At the first access to health care in our hospital, CD4+ cell count and HIV viral load (VL) were worse in TG patients, with a median baseline CD4+ cell count below 350 cells/µl and a higher median HIV VL, both in naïve patients (28.6%) and in pre-treated patients whose therapy was interrupted owing to access-related issues (46.4%). These data show high vulnerability to HIV infection among TG and highlight that issues associated with access to health care can cause delays in the diagnosis and treatment of HIV infection. Based on our results, we think that the health care system should adapt to the sociodemographic, clinical, and behavioral characteristics of TG people living with HIV and develop specific, targeted preventive programs to address the vulnerability of this group.