Background: Blockchain is a technological innovation, and its benefits such as decentralized transactions without a trusted third party, improvements in traceability and efficiency can potentially facilitate complex challenges faced by supply chains (Hughes et al., 2019; Saberi et al., 2019). However, solutions are rather in a demonstration stage, which raises the question of what barriers prevent organizations from adopting blockchain (Kouhizadeh et al., 2021). Especially small and medium-sized enterprises (SME) have been neglected in blockchain adoption studies (Wong et al., 2020). However, research recognizes that they should be considered separately because of their specific needs (Chouki et al., 2020). Moreover, the pre-decision stage of the adoption is of interest, as blockchain applications for the supply chain are still in a pilot phase (Y. Wang, Singgih, et al., 2019). Research Question: What barriers do SMEs face during the pre-decision stage of blockchain adoption for supply chain? Theoretical Framework: A framework developed by Kouhizadeh et al. (2021) containing barriers that impede blockchain adoption for supply chains is contextualized in the pre-decision phase and focused on SMEs. Methodology and Data Collection: This thesis follows a qualitative, deductive approach. An exploratory single case study was conducted to collect data through semi-structured interviews. This sheds light on the blockchain adoption from the perspective of a Swedish SME in the pre-decision stage that intends to use blockchain for sustainable water management in an agricultural supply chain. Complementary to this, blockchain experts are interviewed to enrich companies' responses that cannot fully illuminate the barriers due to their limited knowledge. Findings: Supply chain barriers emerged as the most important, especially 'SC2- Problems in collaboration, communication, and coordination in the supply chain', and 'SC1- Lack of customers' awareness and tendency about sustainability and blockchain technology'. Furthermore, four characteristics were identified that significantly influence the perception of the barriers in the setting studied: The proactive commitment to adopting blockchain, the affinity and attitude toward information technology (IT), trust, and financial support. Conclusions: Several managerial and theoretical implications result from the study, as well as suggestions for further research. These include that SMEs and consultants should consider the characteristics that influence perceptions of barriers in order to prioritize the barriers, and also in research they should be more emphasized to enhance transferability of blockchain adoption research. Limitations include that the case study was conducted on a single SME in Sweden, therefore a validation of the results in other SMEs would be beneficial. In addition, a longitudinal study could shed light on how the barriers change during the adoption process, and further research could reveal the strategies that SMEs use to overcome the barriers.