Microbial inoculants (MI), a biofertilizer, composed of many different beneficial microorganisms has positive role on seed germination and growth of plants. In the present study, its efficacy on seed germination and seedling growth of Albizia lebbeck in the nursery was studied. The seeds were sown in polybags filled with a mixture of forest soil and cow dung (3:1) and treated with 0.1%, 0.5%, 1%, 2%, 5% and 10% concentrations of MI. Most of the parameters studied (seed germination, shoot and root lengths, dry weights of shoot and root, collar diameter, leaf number etc) were found maximum in 2% of MI . Although the highest vigor index, volume index and quality index (7053, 3738 and 1.106, respectively) were found in 2% MI, but the highest sturdiness (65.95) was found in 1% MI solution. The nodule number was higher at a very low (0.5%) concentration of MI but it normally decreased with the increase of concentration. Total pigment content in leaf was recorded highest (112.86 mg.L -1 ) in 2% of MI. Therefore, MI influences seed germination and seedling growth of A. lebbeck and the low concentration (2%) of the inoculant can be recommended for getting maximum seed germination and seedling growth of the species studied. , is a moderate to large deciduous tree with a straight bole and broad crown under the family Leguminosae (Mimosoideae). The species is widely spread in the world, and is native to Asia, Africa and Northern Australia. It grows naturally in Nepal, Bangladesh, Myanmar and Pakistan and has been cultivated in tropical and subtropical regions in Northern Africa, the West Indies, South America, and south Asia. Extensive plantations had been established in Nepal and in South India (Luna, 1996;Kumar et al., 2010;Elzaki et al., 2012;Missanjo et al., 2013). The wood is excellent for furniture and timber for general uses, post, piles, fuel wood and charcoal. The tree is used as ornamental and nurse tree for tea gardens, coffee and cocoa orchards (Mishara et al., 2010;Missanjo et al., 2013;Shaikh et al., 2014). It is a soil improver because of its inherent ability to fix nitrogen (Qadri and Mahmood, 2005). The leaves are excellent fodder for livestock. The species is also very useful for the rehabilitation of degraded lands because of its rapid growth, ability to fix nitrogen and tolerance for a range of soil conditions (Luna, 1996;Qadri and Mahmood, 2005;Mishara et al., 2010;Bobby et al., 2012;Shaikh et al., 2014). The plant has already been proven successful for afforestation, reforestation, social forestry and agroforestry programs in Bangladesh (Zabala, 1990;Dey, 2006).To fulfill the high demand, many organizations are producing A. lebbeck seedlings in the nursery in Bangladesh to supply those in the plantation programs. Because the plants are grown mostly in unfavorable soil conditions, beneficial soil microorganisms can play a significant role in early establishment and better growth of the inoculated seedlings under field conditions. The microbial inoculant (MI) in this study, with the commercial name "Effe...