A two-year survey of Laguna de Bay, the largest freshwater unit of the Philippines, has just been completed. As far as facilities could he available, the physico-chemical conditions, the biological characteristics, and the fisheries of the lake were investigated. Under UN/EPTA assistance, this work is being continued and will be expanded to cover other physico-chemical factors and the various trophic groups of living plants and animals participating in the food cycle. Present knowledge of this productivity relationships in this lake is discussed.