[en] Takasaki has been taking efforts to contribute the development in the field of radiation processing through IAEA/RCA projects and bilateral cooperations. We are currently conducting the following bilateral cooperations on radiation processing of natural polymers. Indonesia: Development of protein free radiation vulcanized natural rubber latex. China: Research cooperation in the field of application of radiation (information exchange). Malaysia: Radiation crosslinking of starch. Thailand: Radiation processing of silk proteins. Vietnam: Radiation processing of marine carbohydrates. These cooperation researches are aiming at extending the application field of natural polymers produced in South Asia using radiation processing such as degradation, crosslinking, and graft polymerization methods. Though each bilateral cooperation has different target materials, we can proceed the cooperations efficiently by exchanging common radiation phenomena of the targets. Therefore, these cooperations must contribute the establishment of the technologies, which meet the regional demand such as recycling of natural resources and prevention of environmental pollution. We held the workshop concerning research and development on radiation processing techniques of natural polymers with invited researchers from 5 bilateral collaboration countries. In the workshop we had presentations and discussions on the outcomes of the bilateral cooperations. This proceeding compiles the invited and contributed papers that were submitted from the speakers. The 18 of the presented papers are indexed individually. (J.P.N.)