The embryonic and larval development of local Guchibaim, Mastacembelus pancalus (Hamilton) was studied during May to October 2007. This study presents preliminary observations on the embryonic and larval development of Mastacembelus pancalus under laboratory conditions. The parents stock was collected from different places of Mymensingh district. The eggs were obtained through induction of spawning by use of hormones. At fertilization; the eggs were 0.50 mm in diameter. Samples were taken every 10 minutes interval till completion of morula and then every 1 hour interval up to hatching. After hatching, daily observations took place until the attainment of the fingerling stage. The eggs presented coloration varying from yellow to brownish-green. They were spherical, demersal and adhesive. The stages of embryonic development observed with cleavage, followed by blastula, morula, early gastrula, middle gastrula, late gastrula and until hatching of non-pigmented larvae which displayed total average length of 1.3 mm ± 0.22, 35 hours after fertilization. First cleavage was recorded within 1.05 hrs after fertilization and the embryonic rudiments of developing eggs appeared at 24.30 hrs at 27.0-31.0°C. The yolk sac was completely absorbed at 67 hrs during embryonic development on attainment of 5.50 mm total length. At the same time the digestive system became fully developed and the larvae searched for feeding.