~~An evaluation of the Required Safe Egress Time (RSET) is a crucial step in the performance based fire safety engineering design. Pre-evacuation time is also essential of RSET. Consequently, pre-evacuation time and pre-evacuation behavior are currently regarded as the key aspects of evacuation process. This study was conducted to assess pre-evacuation behavior and pre-evacuation time in fire of industrial workers in Thailand. The subjects were observed without the observations were unaware that being observed. Three hundred and seventy five workers in ten medium plastic industries were recruited for the analysis using descriptive statistics. The study showed that pre-evacuation behavior in industrial fire were notifying others, grasping fire extinguishers to put out fire, calling others and repress the alarm bell which were 23.90%, 17.24%, 16.75% and 16.75% among the subjects respectively. After these, pre-evacuation time was assessed and the results showed that majority of subjects selected escape reaction within 300-350 seconds, There was 6% among them who reacted to fire within more than 650 seconds. The pre-evacuation behavior and pre-evacuation time plays a significant role in fire response performance. Moreover, there is a need to reduce pre-evacuation time. Limitations and future work are also discussed.