The first cooperative research under the JSPS Multilateral Program between Japanese and Vietnamese scientists was conducted at the Haiphong Branch of Institute of Oceanography (currently named as Institute of Marine Environment and Resources) on microagal composition and toxin level in shellfish in northern Vietnam. After then various study topics such as classification of potentially HAB species, toxin accumulation in marine organisms, and toxin productivity in the HAB species found in Vietnamese waters have been carried out. .Especially a study. on accumulation mechanism of domoic acid, causative toxin for amnesic shellfish poisoning, in- bivalve and its origin was intensively conducted at Nha Phu bay, Khanh Hoa province, central Vietnam. A/though the research started with various difficulties in available facilities, budgets and human resources, Vietnamese scientists could develop capacity for HAB study both at country and regional levels through the cooperative activities. Results of the study were presented at international meetings, workshops and published in international and national journals. Twelve international and 22 national papers were published based on JSPSVAST collaborative researches during 10 years (2001-2010).