This was a retrospective descriptive study of deaths in the Republic of Kiribati from 2005 to 2014. We determined the proportion of all deaths that are ill-defined and described the characteristics of these ill-defined deaths. There were 5618 deaths between 2005 to 2014; of these 1049 (18.7%) were ill-defined. Of these, 576 (54.9%) were male. Those aged 65 years and above had the highest proportion of ill-defined deaths at 40% (n= 415), followed by children aged 0-15 years (29.6%, n=310). Further, 47.7% (n=500) of ill-defined deaths were reported by staff from health dispensaries. When the ill-defined deaths were further categorised according to their R code (with the R code being a group of ill-defined deaths, with sub-groups), 30.5% (n=320) had unknown cause of death, while 29.3% (n=307) had general symptoms and signs. Almost one fifth of deaths in Kiribati were ill-defined, indicating that the reporting on cause of death can be improved through Medical Certification on Causes of Death training and by other means. Improved cause of death reporting will allow the Ministry of Health and Medical Services to better allocate resources, plan health care service delivery and support the development of evidence based preventative and curative policies.