Tenaris and Sidor Complete Acquisition of Venezuelan HBI Plant.

LUXEMBOURG -- Tenaris S.A. (NYSE:TS) (Buenos Aires:TS) (BMV:TS) (MTA Italy:TEN) further to its announcement on April 27, 2004, confirmed today that, together with Sidor, a Venezuelan steel producer in which it has an indirect investment, it has completed the acquisition from Posven, of an industrial facility for the production of pre-reduced hot briquetted iron, or HBI, located in Ciudad Guayana, Venezuela. The acquisition was made through Materiales Siderurgicos MASISA S.A., a company constituted in Venezuela and currently held 50.2% by Tenaris and 49.8% by Sidor, for the price of US$120 million.

The facility, which has a nominal annual design capacity of 1.5 million tons of HBI and was constructed by Raytheon Engineers & Constructors using technology developed by Hylsamex, a Mexican steel producer, has been shut down since shortly after commencing operations in 2000.

Tenaris is a leading global manufacturer of seamless steel pipe products and provider of pipe handling, stocking and distribution services to the oil and gas, energy and mechanical industries and a leading regional supplier of welded steel pipes for gas pipelines in South America. Domiciled in Luxembourg, it has pipe manufacturing facilities in Argentina, Brazil, Canada, Italy, Japan, Mexico and Venezuela and a network of customer service centers present in over 20 countries worldwide.