Objective: To describe patterns of uptake of Indigenous-specific health assessments and associated follow-up items, and examine the barriers and enablers to delivery and billing of follow-up over the first 3 years of implementation of the Indigenous Chronic Disease Package (ICDP). Design, setting and participants: We used a socioecological approach to analyse data derived from the Sentinel Sites Evaluation of the ICDP - with data from 24 sites across Australia. Administrative data (1 May 2009 to 30 May 2012) and program data (1 March 2010 to 30 May 2012) were provided by the Department of Health. Data on barriers and enablers to follow-up of health assessments were obtained from community focus groups, in-depth interviews and discussions with key informants (1 November 2010 to 30 December 2012). Main outcome measures: Monthly number of Medicare Benefits Schedule items claimed for Indigenous-specific health services and follow-up; qualitative data on enablers and barriers categorised according to patient, patient-health service relationship, health service or organisation, community and policy environment levels or influence. Results: There was an increase in the uptake of health assessments, but relatively limited delivery of follow-up care and billing for Indigenous-specific follow-up items. Follow-up was constrained by factors that operated at various levels: patient, interpersonal, health service, community and policy. Constraints included practitioners' lack of awareness of item numbers, staffing, poor state of clinical information systems, billing against non-Indigenous-specific items or more general follow-up items, emphasis on health assessments with less attention to requirements for follow-up, limited capacity to arrange and facilitate follow-up, and communication and transport challenges for patients. Conclusions: Work is required across various levels of the system to address barriers to follow-up care. Enhancing follow-up care is vital to achieving health benefits from the large financial and human resource investment in health assessments.