A study on the taxonomic comparison of five populations of the climbing perch, koi, Anabas testudineus was conducted from five regions of Bangladesh viz. Chittagong, Dhaka, Khulna, Rajshahi and Sylhet. The comparison was based on the morphometric and meristic data of the populations collected over a period of 4 months from July to October 2003. The average total length, standard length, post orbital length, eye diameter, length of base of the dorsal and anal fin of the population of Khulna region were higher than those of the other four populations. All the population characteristics of Chittagong region revealed significant difference (P<0.05) than those in Khulna. Average meristic characters showed no difference (P>0.05) in all five populations in dorsal fin rays, pelvic fin rays, anal fin rays, and number of scale below and above lateral line. However, number of dorsal spine was found to be significantly higher (P<0.05) in Dhaka region than those in other regions. Number of caudal fin rays was also higher in Dhaka region. Five different body proportions viz., Standard Length: Head Length; Standard Length: Body Depth; Head Length: Eye Diameter; Head Length: Pre-orbital; and Head Length: Post orbital were recorded and significant differences at 5% level were obtained.