Purpose: This study traced the origins of subsistence Farmers' technology adoption attitudes and extracted the critical elements in their decision making systems. Design/Methodology/Approach: The analysis was structured using a model based on the Theory of Planned Behaviour (TPB). The role of a "bargaining process" was particularly explored to partially represent the socio-cultural influences, as it became clear social influences were important to decision-making in subsistence situations. The adoption of an improved paddy-prawn system in Indonesia was used as a case study. Findings: The results highlighted the Farmers' use of rational strategies and the socio-cultural interactions in decision-making. Before they would fully adopt the farmers needed to confirm that a new technology was significantly superior to the existing system and could provide a secure income. The role of, largely, a family bargaining process was found to be important. Practical Implications: The model parameters offer a realistic description of the subsistence farmers' decision-making process and consequently provide food for thought when developing extension programmes. Originality/Value: The use of the bargaining process has not been considered in previous studies using a TPB model. This bargaining process seemed to integrate different sets of decision criteria the farmers had learned and in which they believed. Such a process indicated the importance of considering the adoption decision and the relevant changes resulting from the farmers' cognition and interaction. (Contains 4 tables and 4 figures.)