Sepsis is a major health problem with recent increase of incidence. One of life-threatening complications of sepsis isDisseminated Intravascular Coagulation (DIC). DIC in sepsis can trigger an increase of platelet destruction which can beassessed by platelet count and platelet index. Hence, this research aimed to analyze the correlation of platelet count andplatelet index to the prognosis of adult septic patients. This research was then performed with a retrospective longitudinalstudy design. This research used the medical record data of adult septic patients at the Dr. Wahidin Sudirohusodo GeneralHospital in Makassar. The data of platelet count and platelet index were collected from routine blood of the patients for thefirst time they were diagnosed with sepsis. In total, this research was performed on 100 adult sepstic patients. Fifty of thosepatients had a good prognosis (cured), while the other fifty patients had a poor prognosis (died). Statistical results showedthat the platelet count in the adult sepsis patients with a poor prognosis was significantly lower than those in patients with agood prognosis with median/minimum-maximum of 157,000/12,000-626,000 and 329,000/96,000-801,000, respectively(p=0.00). It was also known that there was no significant difference of MPV values between patients with poor prognosis andpatients with good prognosis with Mean±SD of 9.54±1.44 and 10.08±2.09, respectively (p=0.138). Unlike MPV values, PDWvalues in patients with poor prognosis were significantly higher than those in patients with good prognosis with Mean±SDof 16.7±6.26 and 11.25±2.13, respectively (p=0.00). Thus, it can be concluded that there was an inverse correlation betweenplatelet count and PDW value (r = -0.58). PDW value, as a result, could be used as a prognosis marker for adult septicpatients. However, it was recommended to perform further research as a prospective study by removing the possibility ofbias.