Larvae of fishes and decapods found in zooplankton collections from two stations (Mankule and Patalganga) in Amba estuary adjoining Mumbai harbour were studied during 1989-90 covering three seasons. The percentage contributions of decapods and fish larvae to the total zooplankton population were 3.63 and 0.03 respectively. In the assessment of larval stocks environmental parameters and the presence of adult fish caught in the area were considered. The estuarine area supported fairly high fishery potential as compared to the nearshore coastal waters of Mumbai. The total fish catch showed an increasing trend during September (av. 21.1 kg/hr). Harpadon nehereus, Coilia dussumieri and Johnius dussumieri were recorded in the estuary irrespective of tide, time or season. The decapod larvae of Acetes, Lucifer, Metapenaeus dobsoni, M. affinis, alpheids, palaemonids (Macrobranchium sp.) and crab zoeae were common in the collections. The larvae of fishes mainly belonging to the families of Engraulidae and Clupeidae indicated the presence of possible breeding, spawning and nursery grounds in the vicinity of Dharmtar creek.