Železnatý pramen, Mineral spring in Karlovy Vary, Czech Republic.

Železnatý pramen is the 16th Karlovy Vary mineral spring, on the right bank of the Teplá on a raised terrace above the river near the Business Academy building. It is the coldest of the town's springs at 11.9 °C, with an output of 1.8 litres per minute and 1,600 mg of CO2 per litre. Its water is piped into a small columned pavilion, sometimes called a colonnade.

The spring was first recorded in 1852 on the slope above the right bank of the Teplá, about 400 metres before its confluence with the Ohře. From 1856, on the advice of the physician Rudolf Mannl, its water was used for drinking cures, and four years later the Železité lázně baths opened nearby. In the 1920s the outlet was shifted a few metres during construction of the school building and piped into a small columned pavilion; after repairs in 1961 and a full reconstruction, the pavilion reopened on 27 October 1990.

The spring's name comes from its high iron content, which once stained the slope ochre. From 1856, on the advice of Dr. Rudolf Mannl, its water was used for drinking cures, and the nearby Železité lázně opened four years later for bathing. Today the spring is not a declared natural healing source and stands apart from the spa centre.

The spring sits on an elevated terrace above the right bank of the Teplá, by the Business Academy on Bezručova Street, away from the spa centre. It is freely accessible, but a note from April 2019 records it closed for technical reasons until further notice. The outlet is beside a busy road with car and bus traffic.

The spring's water differs from all other Karlovy Vary sources through its high iron and arsenic content, which once stained the slope ochre. Its yield is only 1.8 litres per minute, and it is not registered as a natural healing source.