Purpose: The purpose of the study was to understand the adoption process of ricefield based fish seed production (RBFSP) that has been developed, promoted and established in Northwest Bangladesh. Design/Methodology/Approach: Quantitative investigation based on regression analysis and qualitative investigation using semi-structured interview were carried out to enhance understanding of the adoption process of RBFSP. Findings: A quantitative investigation showed two variables, the area of rice-plot stocked and access to tilapia broodfish, predicted 57% of variability of RBFSP adoption. A later qualitative investigation with different groups of people from communities where RBFSP was established showed ecological and complex socio-cultural factors to be responsible for its adoption or rejection by farming households. In an ecological context, the development of the rice-plot environment and increased fish production in rice-plots and ponds were major factors influencing adoption by farming households. In the case of farming families, the technology helped to meet the basic food needs of household members, particularly women, children and the elderly. There was an important temporal aspect of the benefits delivered by the approach, since fish consumed and income provided for households occurred during the "hungry gap"; RBFSP can be regarded as a coping mechanism for households' seasonal vulnerability. Development of networks among seed producers and fry traders reinforced the adoption process. Practical Implications: Loss in access to suitable ricefields through land tenure change was identified as the most important factor constraining sustained adoption of RBFSP by farming households. Originality/Value: The quantitative investigation showed that the two variables possessed limited explanatory power for the adoption process of RBFSP, however, the qualitative investigation identified complex factors that contributed to the adoption process of the technology. (Contains 6 tables, 2 figures, and 1 note.)