Abstract. Palupi M, Fitriadi R, Wijaya R, Raharjo P, Nurwahyuni R. 2021. Diversity of phytoplankton in the whiteleg (Litopenaeus vannamei) shrimp ponds in the south coastal area of ??Pangandaran, Indonesia. Biodiversitas 23: 118-124. Intensive shrimp farming in ponds is characterized by high stocking densities, complete feeding in quality and quantity, and good environmental control to produce the maximum quantity of shrimp in a fixed area. Phytoplankton is a bioindicator affecting the productivity of whiteleg shrimp in ponds. Currently, intensive shrimp farming activity is carried out on the south coast of Java, which utilizes sandy soil with a biofloc system, but the production has not been optimal. The objective of this study was to analyze the diversity and abundance of phytoplankton and water quality in the traditional and intensive whiteleg shrimp ponds in Pangandaran, West Java, to support sustainable pond management. The objective of the study was achieved by calculating the abundance, diversity index, evenness index and dominance index of planktons in intensive and traditional ponds. The study results showed that Chrysophyta division had the highest abundance and species number in both intensive and traditional ponds. The most abundant phytoplankton found in the intensive ponds was Halosphaera viridis (3143.88 ind/m3), and that in the traditional ponds was Rhizosolenia stolterfothi (1414.746 ind/m3). The phytoplankton diversity index (H') in the intensive ponds was 1.95 and that in the traditional ponds was 2.17. The dominance index value in the intensive ponds was 0.18 and in the traditional ponds 0.15. The abundance of phytoplankton is a limitation of the production success of whiteleg shrimp farming.