Introduction:Hospitalizations for ambulatory care-sensitive conditions (HACSC) are considered an indicator of the effectiveness of primary health care (PHC). High rates of HACSC represent problems in the access or the quality of health care. In Brazil, HACSC rates are high and there are few studies on the factors associated with it. Objective: To evaluate the access to PHC offered to children and adolescents hospitalized due to ACSC and analyze the conditioning factors. Method: Cross-sectional study with a quantitative and qualitative approach. Five hundred and one (501) users (guardians/caregivers) and 42 professionals of PHC units were interviewed over one year. Quantitative data were obtained using Primary Care Assessment Tool validated in Brazil (PCATool-Brazil), while qualitative data were collected by semi-structured interview. The independent variables were: age, maternal education, family income, type of diagnosis, and model of care offered, and the dependent variables were access and its components (accessibility and use of services). Results: Sixty-five percent (65.2%) of hospitalizations were ACSC. From the perspective of both users and professionals, access and its components presented low scores. Age, type of diagnosis, and model of care affected the results. Conclusion: The proportion of HACSC was high in this population. Access to services is inappropriate due to: barriers to access, appreciation of the emergency services, and attitude towards health needs. Professional attitudes and opinions reinforce inadequate ideas of users reflecting on the pattern of service use.