Importance of the work: Track the abundance, population size and distribution of Water monitors in an area of urban, changing land use.Objectives: To examine the presence, abundance and the distribution of water monitors in the Kasetsart University Bangkhen Campus.Materials & Methods: Two survey methods were used-line transects and live traps to implant a microchip (PIT tag) on water monitors in the study area. Population size was analyzed using the R program in the package Rcapture.