Neurosecretory cells (NSCs) with endocrine functions have been described in majority of triploblastic animals. Since the initial description of these cells in Lumbricus terrestris there have been numerous studies on the structure, types and role of these cells in the central nervous system (CNS) of oligochaetes. According to Scharrer and Scharrer [5], almost one half of the cerebral ganglia in oligochaetes is glandular. In fact NSCs within the CNS of earthworms are regarded as the source of “vascular” hormones controlling many biological activities such as growth, osmoregulation, reproduction, thermal acclimation, food intake , regeneration and light reaction . In absence of any definite neurohaemal organ, as found in polychaetes and arthropods, the neurosecretory system in oligochaetes deserve special attention because of being the first class of coelomates with closed vascular system. Due to difference in nomenclature of NSC types, variations in their morphology and the modes of release of hormones in absence of a welldeveloped storage release organ , we have studied the neurosecretory systems in the cerebral ganglia of some tropical earthworms belonging to different ecological categories viz.; surface living phytophagous epigeic (Eudrilus eugeniae, Family: Eudrilidae ), geophagous horizontal burrower endogeic (Metaphire posthuma, Family: Megascolecidae), geophagous vertical burrower endoanecic (Eutyphoeus gammiei, Family: Octochaetidae) and phytogeophagous vertical burrower anecic earthworm (Metaphire houlleti, Family: Megascolecidae).