Deaths from Plasmodium knowlesi malaria have been linked to delayed parenteral treatment. In Malaysia, early intravenous artesunate is now recommended for all severe malaria cases. Researchers describe P. knowlesi fatalities in Sabah, Malaysia, during 2012–2014 and report species-specific fatality rates based on 2010–2014 case notifications. Sixteen malaria-associated deaths (caused by PCR-confirmed P. knowlesi, P. falciparum, and P. vivax and microscopy-diagnosed “P. malariae” were reported during 2012–2014.