Globally, health systems accountability and engagement are increasingly claimed to be vital means to improve services by providing mechanisms for potential beneficiaries to contribute to the design, implementation, and evaluation of service delivery. In Kenya, these have taken the form of hospital boards, health facility committees, patient and facility service charters, and suggestion boxes. However, there is little information available on the factors that impact on the performance of such accountability mechanisms. This thesis addresses the shortfall, by investigating process issues that influence the performance of accountability initiatives. Primary research was conducted in a rural district through a cross-sectional survey of households clustered around four public health facilities. Following a pilot study, data on accountability mechanisms supporting service delivery were collected through a mapping exercise involving in-depth interviews and facility audits. Data on the use of these were then collected through a large cross-sectional household survey, participant observation and focus group discussions. Analysis focused on accountability mechanisms within the health facilities and on issues around the relationship between those facilities and the local community. This was supplemented by user experiences of services where this was central to an understanding of accountability structures performance. The research identified health facility committees and Service Charters as the main accountability mechanisms adopted. Further analysis showed that four main underlying factors - accessibility/proximity, trust, power and responsibility –influenced both of these. The context of the health system and cultural practices were also important determinants of performance, either constraining or enhancing their impact on service delivery. These findings suggest that emphasis on the structure of accountability and engagement mechanisms, or adopting simple measures of outcome, are unlikely to account for how and why accountability mechanisms perform as they do. Processes that sustain and are sustained by accountability mechanisms need to be considered including the selection process of health facility committee members, the use of effective communication methods with the local community, and appropriate national regulation. In addition, these efforts should always take into account the health needs of the local population, their cultural practices, and the policy context within which these mechanisms are expected to operate.