148 species of zooplankton were recognized during 12 cruises from Aug (2009) to July (2010) at 4 stations in Nha Phu estuary and Binh Cang bay. Copepod had 94 species (63.51 percent of total) and followed by Cnidaria and Tunicata (15 speciej). Station 2B had the highest value of zooplankton species (76 speciej) in August, 2009 .while station 5 only had 7 species. In November, 2010. Density oj zooplankton in Nha Phu was higher than in Binh Cang bay. Highest density occurred at station 5 (Sep, 2009) with 118.486 inds/m3 and lowest in Mar, 2010 with 890 inds/m3. Density oj zooplankton was reduced Jrom Nha Phu to Binh Cang bay while the richness species was increased. The average oj Shannon index (H') was Ilowest at station 5 (1.39 +/- 0.26) and highest at station 2B (2.58 +/- 0.67).