A study was conducted for one year to record live fuel moisture contents (LFMC) of dominant tree species of tropical thorn forest ecosystem in Tirunelveli, Tamil Nadu. Standard methods and protocols were followed for the sample collection, processes and analyses. The mean live fuel moisture values showed that all the dominant tree species of the tropical thorn forests possess high fire behaviour (LFMC values ranged from 101% to 125%). The LFMC had relationships with environmental factors (rainfall, temperature, humidity, rainy days, hours of sunlight availability). The tree species had the uppermost LFMC in the wettest month and the lowermost in the peak summer. The needs for further studies has been emphasized.