Transactional memory is currently a hot research topic, having attracted the focus of both academic researchers and development groups at companies. Indeed, the concept of transactional memory has recently attracted much interest for multicore systems as it eases programming and avoids the problems of lock-based methods. However, up to now, the scheduling of real-time transactions within software transactional memories has not been studied. To address this issue, we present in this paper a real-time software transactional memory, namely RT-STM. We focus on the scheduling of concurrent real-time transactions. In particular, we explore a new heuristic for conflict resolution that reduces the number of deadline violations when scheduling real-time transactions. After having discussed the scalability of various classical STMs under a real-time operating system, we present experimental results that show that RT-STM can improve the performance of transactional memory-based applications on multicore platforms.