This paper reviews the progress and outcomes of rolling out IDSR in South Sudan, using epidemiological and program data for 2019-20 to provide detailed assessments of surveillance priorities, core and support functions, and surveillance system structure and quality. Progress has been made in expanding priority diseases to align with regional epidemiological trends and the International Health regulations 2005. Both timeliness and completeness of reporting improved. Rapid response teams were established. The authors argue that sustained investment of resources towards IDSR implementation has improved the program reporting performance, averting morbidity and mortality, while program funding from domestic resources would be critical for sustainability in the long-term.