Abstract: The present study was conducted at the USDA Biotechnology Laboratory, Department of Biotechnology, Bangladesh Agricultural University, Mymensingh during July 2000-July 2002 to investigate the effect of different concentrations of 2,4-D on callusing and PLB formation; BAP (0, 2, 4 and 6 mg l^-1) and NAA (0, 0.5 and 1.0 mg l^-1) on formation of Protocorm Like Bodies (PLBs) and plantlet regeneration from Dendrobium formosum leaf callus. PLB formation, shoot proliferation, root formation, leaf number, shoot length and root length were recorded. The fastest callusing (9.32 days) and the amount (0.73 g explant^-1) was the greatest with 1 mg l^-1 2,4-D at 20 DAE, also the number of PLB was the highest (10.52 explant^-1) at 60 DAE. Time required for PLB formation was the longest (32.72 days) with 0.50 mg l^-1 2,4-D. Plantlet height, root length and number of shoots, leaves and roots per plantlet showed significant variation due to BAP and NAA addition. BAP at 2.5 mg l^-1 showed the best results in combination with 1 and 2 mg l^-1 NAA.