Bambusa balcooa is one of the priority bamboo species in home gardens of north-east India. Flowering of this bamboo is rarely reported. The species flowered during recent years in Barak Valley of southern Assam, India. The present study reported the floral biology and pollen sterility of B. balcooa in relation to seed set. The study revealed that insufficient separation of palea and lemma, non-exposure of essential whorls, low pollen viability and reduced stigma receptivity prevented seed set. Since this species is monocarpic, absence of seeding questions continuity of the species.