Procalcitonin (PCT) concentration of greater than 10 ng/mL is compatible for septic shock. Its predictive value for survival is not well established, mainly because of much overlap and variation of PCT in this condition. We hypothesized that dynamic change of PCT, rather than PCT itself, is predictive of hospital survival when greater than 10 ng/mL. Thirty-seven septic shock patients with PCT concentration of greater than 10 ng/mL were enrolled in this prospective cohort study. Patients were divided into survivors (n = 25) and nonsurvivors (n = 12) based on 28-day hospital outcome. Subsequent PCT measurements were taken 5 days after enrollment. Sequential Organ Failure Assessment (SOFA) scores were recorded simultaneously. Dynamic changes of the PCT and SOFA score were defined as the difference between the subsequent and initial measurement. There were no significant differences between survivors and nonsurvivors in age, sex, initial measurement of PCT, and SOFA. All survivors had a decrease in PCT concentration; median decrease was 9.73 ng/mL. All nonsurvivors had an increase in PCT concentration; median increase was 5.95 ng/mL. Significant decrease in PCT concentration (>25%) was observed in all the 25 survivors, whereas there was none in 12 nonsurvivors. Procalcitonin of initial, subsequent measurements, and dynamics significantly correlated with their counterparts of SOFA score. In conclusion, significant decrease in PCT concentration, rather than PCT concentration itself, may be a useful indicator of survival in septic shock patients when PCT concentration is greater than 10 ng/mL. Procalcitonin concentration highly correlated with the SOFA score in septic shock patients even when the PCT concentration is greater than 10 ng/mL.