Piestany is a town in Slovakia. It is located in the western part of the country within the Trnava Region and is the seat of its own district. It is the biggest and best known spa town in Slovakia and has around 28,000 inhabitants.

Because of frequent floods in the past, most buildings are dated to the 19th and 20th century. The most notable exception are the ruins of a medieval monastery from the 13th century. The Napoleon Spa is a complex of Neoclassicist spa buildings built between 1822 and 1862. The town’s Catholic church dates from the same era. The Kolonádový most bridge, constructed by Emil Bellus in 1930-33, is a preeminent functionalist construction with many precious art objects.

The Piestany spa has a capacity of two thousand beds (as of 2005) and treats over forty thousand patients a year. More than 60% of the clients are foreigners (mostly from Germany, the Czech Republic, Israel, Austria and Arab Countries). The spa specializes in treatment of chronic rheumatic and arthritic diseases and post-accident lesions of joints and bones.

The spa is located on the Spa Island between two branches of the Vah river, at the site of several hot springs with temperatures of 67-69°C (153-156°F). The water originates in a tectonic break at 2,000 metres (6,600 feet) depth. The sulfate–carbonate water from the springs is used in pools and tubs. Sulfurous mud extracted from the bed of a side channel of the river is also used for treatment in the form of thermal mud pools with temperature 39°C (102°F) and for partial and full body packs. Spring water and mud therapy is complemented by electrotherapy, exercise, massage, medication, and diet.

The spa is operated by the company Slovenské liecebné kúpele. The company was purchased in 2002 by Danubius Hotels Group. A small share is owned by the town. Danubius Hotels Group also owns hotels in Hungary, Mariánské Lázne spa in Czech Republic and Sovata spa in Romania.