Transactional programming promises to substantially simplify the development and maintenance of correct, scalable, and efficient concurrent programs. Designs for supporting transactional programming using transactional memory implemented in hardware, software, and a mixture of the two have emerged recently. However, certain features and capabilities that would be desirable for debugging programs executed using transactional memory are absent from conventional debuggers. Breakpointing is one example of a capability not well supported when conventional debugging technology is applied to transactional memory. We describe techniques by which a debugger may instrument code (or by which a TM library may provide functionality) to direct execution of an atomic block to a code path that facilitates breakpoint handling.