Objectives Thoracic sympathectomy is considered the most effective method to treat palmar hyperhidrosis. We developed a novel approach for thoracic sympathectomy in patients with palmar hyperhidrosis through the umbilicus, using an ultrathin gastroscope. The aim of this study was to evaluate the continuing efficacy and patient satisfaction of this innovative surgery. Methods All procedures were performed under general anesthesia and the patients were intubated with a dual-lumen endotracheal tube. After a 5-mm umbilical incision, the muscular parts of the diaphragmatic dome were incised with a needle-knife and the nasal gastroscope was advanced into the thoracic cavity. The sympathetic chain was identified at the desired thoracic level and ablated with hot biopsy forceps. All patients were followed up for at least 1 year after the procedure through clinic visits or telephone/e-mail interviews. Results From April 2010 to August 2011, a total of 35 patients underwent a transumbilical thoracic sympathectomy. Fifty-seven percent were male patients, with a mean age of 21.2 years (range, 16-33 years). The success rate after 12 months was 97.1% (34 of 35) for isolated palmar hyperhidrosis and 72.2% (13 of 18) for axillary hyperhidrosis. Compensatory sweating was reported in 28.6% of patients at the 1-year follow-up evaluation. There was no mortality, no diaphragmatic hernia, and no Horner syndrome was observed. Quality of life related to hyperhidrosis improved substantially in 27 (77.1%) patients, and improved in 4 (11.4%) patients at 12 months after surgery. A total of 94.3% of patients were satisfied with the excellent cosmetic results of the surgical incision. Conclusions Transumbilical thoracic sympathectomy is an efficacious alternative to the conventional approach. This technique avoided the chronic pain and chest wall paresthesia associated with the chest incision. In addition, this novel procedure afforded maximum cosmetic benefits.