ObjectiveTo investigate the short-term effects of ultrasound-guided percutaneous microwave ablation (MWA) and radiofrequency ablation (RFA) for treatment of thyroid nodules. MethodsTotally 104 patients with 289 thyroid nodules underwent ultrasound-guided internal-cooled MWA and bipolar RFA in our department from July 2009 to January 2011. The outcomes of patients were closely assessed for a short-term of 6 months; the thermal ablation-related side-effects and complications were also discussed. ResultsFocal ultrasound images of the 289 thyroid nodules and the core-biopsy pathology findings of some nodules revealed complete coagulative degeneration of the ablated lesions. Follow-up for 3-6 months showed that sizes of all the nodules decreased to different extents. Only one nodule needed an extra ablation. No severe complications were observed. ConclusionThe ultrasound-guided percutaneous MWA and RFA are effective, minimally invasive, easy to perform and can achieve rapid recovery. The methods can be used for out-patients with nodular thyroid diseases.