The financial remuneration of health workers (HWs) is a key concern to address human resources challenges in many low-income countries. Analyzing the entire set of payments available to HWs is critical to understand the incentives they face, their motivation and performance, and ultimately to devise effective health workforce reforms. In this thesis, I investigate these issues by exploring the complex remuneration of HWs in Sierra Leone, defined as all income sources, both formal (salary, allowances, performance bonus) and informal (per diems, top-ups, private practice, nonhealth activities and illegal incomes). The study adopts a mixed-method approach. At central level, 23 key informants were conducted along with a stakeholder mapping workshop and a documentary review. At district level, 18 key informants were interviewed. Quantitative data were collected through a cross-sectional survey of 266 public HWs at primary healthcare level in three districts. Additionally, HWs were given a logbook to daily record their activities and incomes. Quantitative data at individual level were complemented with 39 in-depth interviews with a sub-sample of the same HWs. The analysis carried out in this thesis, first, sets the background to the complex remuneration by describing the incentive environment available to HWs as it developed during the post-conflict period, through policy-making processes at macro (central) level. It then investigates how the political economy dynamics between District Health Teams and NGOs at meso (district) level contribute to re-shape the incentive package. Moving to the micro (HW) level, I estimate the absolute and relative contribution of each income and I find that, while earnings from salary represent the largest share, HWs’ income is fragmented and composed of a variety of payments. Further data analysis shows that the determinants of the incomes are not in line with policies defined at national level and are influenced by the district of posting. Furthermore, the HWs’ narratives reveal the relevance of the features of each of their incomes (e.g., amount, regularity, reliability, ease of access, etc.) and the income use strategies through which HWs ‘manage’. Finally, I investigate whether the complex remuneration affects what HWs do or if there are other factors which constrain and/or influence HWs’ activities and service delivery. Findings from this research have important implications for how we go about (re)thinking financial incentive strategies. HWs’ income comes from a variety of sources, which they use differently. This questions the assumption of the fungibility of payments and highlights the potential consequences of increasing one rather than another of HWs’ incomes. Moreover, it is shown that the alignment of policies and incentive packages at central level may not be sufficient as dynamics at district level play a key role in influencing both HWs’ incomes as well as the activities they perform, thus effectively modifying incentive package and service delivery. From a methodological perspective, this thesis contributes to developing data collection and analysis techniques on the complex remuneration of HWs, which are relevant for a potential cross-country research agenda.