The contribution of inadequate health worker numbers and emigration have been highlighted in the international literature, but relatively little attention has been paid to absenteeism as a factor that undermines health-care delivery in low income countries. We therefore aimed to review the literature on absenteeism from a health system manager's perspective to inform needed work on this topic. Specifically, we aimed to develop a typology of definitions that might be useful to classify different forms of absenteeism and identify factors associated with absenteeism. Sixty-nine studies were reviewed, only four were from sub-Saharan Africa where the human resources for health crisis is most acute. Forms of absenteeism studied and methods used vary widely. No previous attempt to develop an overarching approach to classifying forms of absenteeism was identified. A typology based on key characteristics is proposed to fill this gap and considers absenteeism as defined by two key attributes, whether it is: planned/unplanned, and voluntary/involuntary. Factors reported to influence rates of absenteeism may be broadly classified into three thematic categories: workplace and content, personal and organizational and cultural factors. The literature presents an inconsistent picture of the effects of specific factors within these themes perhaps related to true contextual differences or inconsistent definitions of absenteeism.