Objective To investigate the prognostic significance of serum procalcitonin (PCT) and C-reactive protein (CRP) in patients with sepsis and those with septic shock. Methods Fifty-nine patients were divided into sepsis and septic shock groups, as well as survivor and non-survivor groups, according to the severity of the disease and patient survival. Serum PCT and CRP measurements at the time of hospitalization in the intensive care unit were examined. Results On the 2nd, 3rd, and 5th days, the CRP level was higher in the non-survivor group than in the survivor group, and the serum CRP level was higher in patients in the septic shock group than in patients in the sepsis group. Regarding changes in serum PCT level in each group, the levels of PCT were significantly different between non-survivor and survivor groups, whereas they did not differ between patients in the sepsis and septic shock groups. Serum PCT kinetics (Delta PCT) were similar between groups. Conclusions Serum PCT and CRP have good clinical diagnostic and prognostic value for patients with sepsis and septic shock. Kinetic studies of PCT and CRP can improve sensitivity and accuracy when evaluating the prognosis of patients with sepsis and those with septic shock.