Toronto, ON, August 5, 2004 – Argentex Mining Corporation (OTCBB: AGXM) is pleased to announce that a petrographic study has been completed on previously analyzed samples collected from the Los Menucos Gold District during Argentex’s first field program in Rio Negro.The Rio Negro program is being conducted in parallel with exploration at the company’s Pinguino property in Santa Cruz Province.Results of the initial Rio Negro geochemical analysis were announced in a press release on June 30, 2004.

Highlights of the report indicate that multiple rock samples contain native gold mineralization as well as a silver sulphide, possibly acanthite, a most important silver ore. All the samples have typical epithermal textures and associated alteration (clay + sericite) of the felsic volcanic host rock.

Petrographic testing, which involves the use of a microscope to examine the optical properties of separate minerals contained in a sample, was conducted to assess the mineralogy, textures and alteration minerals of the Rio Negro gold discovery.All minerals have different optical properties, allowing for reliable identification using this method of testing.

The discovery of gold in its native form suggests a simple ore metallurgy at surface which would make the ultimate process of gold extraction easier and lower cost than a complex suite of ore minerals.

“These results substantially increase our understanding of the discovery mineralization in Rio Negro,” said Ken Hicks, Vice President of Exploration for Argentex. “This detailed work, together with other surface geological data that we have collected, confirms the presence of a low sulphidation epithermal precious metal environment within our Rio Negro property.This type of mineralization is also found in a high grade gold-silver deposit producing in Argentina, as well as in producing properties in Japan and the United States.An aggressive follow-up program is planned to commence in September.”

The petrographic study was conducted by Craig Leitch (Ph.D, P.Eng.) through the services of Vancouver Petrographics Ltd, Langley, British Columbia.

ABOUT ARGENTEX:
Argentex Mining Corporation is a junior mining exploration company with significant holdings in the Patagonia region of Argentina. The company currently owns mineral rights to 30 properties with over 336,000 acres (132,000 hectares) of highly prospective land, located in the Santa Cruz and Rio Negro provinces of Argentina. Argentex is well funded for its 2004 exploration program. The company trades under the symbol AGXM on the OTCBB.

FURTHER INFORMATION:
Argentex Mining Corporation
Investor Relations
1-888-601-8366
[email protected]

Information Regarding Forward-Looking Statements: Except for historical information contained herein, the statements in this Press Release are forward-looking statements that are made pursuant to the safe harbor provisions of the Private Securities Litigation Reform Act of 1995. Forward-looking statements involve known and unknown risks and uncertainties, which may cause Argentex's actual results in future periods to differ materially from forecasted results. These risks and uncertainties include, among other things, volatility of commodity prices, product demand, market competition, and risks inherent in Argentex's operations. These and other risks are described in the Company's Annual Report on Form 10-K and other filings with the Securities and Exchange Commission.

Cautionary Note to US Investors: This news release may contain information about adjacent properties on which we have no right to explore or mine. We advise U.S. investors that the SEC's mining guidelines strictly prohibit information of this type in documents filed with the SEC. U.S. investors are cautioned that mineral deposits on adjacent properties are not indicative of mineral deposits on our properties. This news release may contain forward-looking statements including but not limited to comments regarding the timing and content of upcoming work programs, geological interpretations, receipt of property titles, potential mineral recovery processes, etc. Forward-looking statements address future events and conditions and therefore involve inherent risks and uncertainties. Actual results may differ materially from those currently anticipated in such statements.