Inborn errors of immunity (IEI) (also known as primary immunodeficiencies) is an umbrella term for a growing group of over 450 different disorders that are characterized by defects in some of the components of the immune system. IEI are chronic diseases of genetic origin that render individuals suffering from them susceptible to infections. The mainstay of treatments for most patients with IEI, that is, predominantly antibody deficiencies is immunoglobulin replacement therapy (IRT), which is commonly delivered intravenously. Immunoglobulin (IG) therapy contains antibodies to compensate for the defective immune system's inability to produce them. Individuals with IEI need IRT regularly throughout their lives to help combat infections and prevent organ damage. Without IRT, they are in danger of suffering from morbidity, poor quality of life, and reduced life expectancy. In the last 20 years, the use of IG preparation has tripled and this is partly attributed to the growing awareness and improved diagnoses of IEI cases. IG preparations are also used for the treatment of other medical conditions including secondary immunodeficiencies and autoimmune diseases. As IG is derived from human plasma, there are concerns about the availability of supply, particularly to treat life-threatening conditions that cannot be improved with other medications. It is estimated that 75% to 80% of IEI patients do not have access to adequate IG therapy throughout the world. This concern of supply and other challenges faced by patients with IEI in Malaysia are described from the patients' perspective.