PURPOSE: To report the current trends of Korean duplicated thumbs and their reconstructive surgery based on Iowa system performed during the last five years. MATERIALS AND METHODS: We performed retrospective review of all (164) patients who had performed operations between 2003 and 2007. Out of all, 109 were male and 55 were female. The age at the time of surgery ranged from six months to 46 years. Data analysis was done by using information from preoperative radiographs and patients'chart including operative records, etc. RESULTS: Wassel type IV was the most common one, and type II was the next. The thumbs were involved as follows: bilateral in nine patients; right, 100; left, 55. In right duplicated thumb, males had about 2.45 more times than females. Eighty five percent of all were 24 months or less: their average body weight was 2.72 kg; average body weight at surgery, 9.07 kg (7.7~10.3 kg); average age at surgery, 9.98months (6~19months). In age distribution of their parents, each average age of fathers and mothers was 34.3 and 32.5 years old. And 10.1 percent of all had combined anomalies. Though there could be some discrimination between radiological types and intraoperative findings on cartilaginous epiphyseal portions, surgical procedures were simple ablation, central resection followed by reconstruction, and combination with radial remnant tissue portions after resection of radial extradigital bone through preoperative findings including radiographs based on Iowa system. CONCLUSIONS: Surgical procedures for duplicated thumb are not ablation but reconstruction. At the appropriate time and optimal procedures are needed for satisfactory postoperative results.