In this study, a shut-down period of a hazardous waste incinerator was considered as two separate phases: the last waste feeding phase and the first cooling phase. Solid, liquid, and gas samples were taken separately for the two phases. Analysis results of the samples were used to compare PCDD/F characteristics of the phases. Additionally, start-up PCDD/F results of the same facility published in some previous studies were used in assessments. The findings showed that congener profiles of the shut-down and the start-up periods were highly similar. On the other hand, concentration levels of the shut-down phases, which indicate an intense memory effect for PCDD/Fs, were lower than the corresponding start-up phases. Furthermore, furan/dioxin ratios and PCDD/F removal efficiencies obtained in the shut-down period were substantially different from the start-up. Therefore, according to the author, it seems like an obligation to perform period-specific management strategies in start-up and the shut-down periods of incinerators.