Obsessive-compulsive disorder (OCD) is a chronic, disabling disorder. Psychosurgery may be indicated for a subset of patients for whom no conventional treatment is satisfactory. This paper focuses on the stereotactic subcaudate tractotomy (SST). Thus far, these procedures have been carried out using frame-based stereotactic techniques. However, modern - highly accurate - frameless stereotactic procedures have successfully been introduced in neurosurgical practice. We developed a novel frameless stereotactic subcaudate tractotomy procedure with promising initial results in a patient suffering from intractable OCD. This is the first report on frameless SST. Future studies should examine whether other ablative stereotactic psychosurgery procedures can be done using frameless stereotactic methods.