We aimed to describe the knowledge of HIV seropositive mother on the children immunization schedule and know the reasons for their non-compliance to the children immunization schedule. This is a descriptive study with qualitative approach carried out in the outpatient clinic of a public institution, in Fortaleza-CE, Brazil. The subjects were 16 mothers or caregivers of children up to two years of age exposed to HIV/AIDS. Data collection happened through semi-structured interviews conducted from January to March 2012. Two categories emerged from the analysis: Lack of knowledge of mother about special immunization schedule for children with HIV and Reasons for non-compliance to special immunization schedule. Mothers presented poor knowledge, fear and disinterest in the information on the disease and preventive measures, as well as the difficulties faced. Health professionals should promote strategies with these mothers seeking integration, commitment and comprehension of the importance of immunization in children.