Concealment of diagnosis is one of the most important manifestations of HIV-related stigma, which is a major barrier to addressing the growing HIV epidemic in Russia. The purpose of our research was to understand how and why people living with HIV (PLHIV) conceal their HIV status in medical settings. We analyzed data collected through two major Russian online forums for PLHIV. We found that concealing HIV status in medical settings is connected to worries about breach of confidentiality, denial of quality medical care, and judgment from health care providers. PLHIV discuss the dilemmas between risks of disclosing and potential legal or health-related consequences of concealment. We identified strategies that PLHIV use to conceal their status including falsifying medical records, hiding test results, and offering payments to doctors. Understanding status concealment is important for building more effective interactions between health care providers and PLHIV, at both the individual and the institutional levels.