VANCOUVER, BRITISH COLUMBIA--(Marketwire - May 17, 2011) - Prospero Silver Corp. (News - Market indicators) (the "Company") is pleased to report the results of 2,145 meters of drilling in 8 core holes at its San Luis Del Cordero Project in central Durango State, Mexico. The results from this second phase of drilling at San Luis Del Cordero show a distinct zone of higher grade silver near the historic Santa Rosa Mine, a new zinc rich area in the southern part of the district and expansion at depth of the Sta. Rosa East Skarn copper/silver mineralization.

• Two holes explored the extension at depth of the historic Sta Rosa vein
• Two holes targeted the new "Canal Zone" in the southern part of the district
• Four holes targeted the Sta. Rosa East Skarn Zone

Silver Rich Zone: Drilling under and to the west of the historic Sta. Rosa Mine was designed to explore further the higher grade silver values reported in previous drilling campaigns by other companies (SL-00-1 & HCSR-1) ca 2007. Drill holes PSLC-14 and PSLC-16 show the vein persisting at depth and include high grade silver intercepts of 684 g/t and 781 g/t with true widths of 2.82 meters 2.35 meters, respectively. These intersections indicate elevated silver grades are persisting up to 220 vertical meters below the surface. The mineralized zone currently >300 meters in length is increasing in size and remains open at depth and to the west (see longitudinal section) under jasperoid-bearing limestones. The average grade of 4 holes (SL-00-1, HCSR-1, PSLC-14 and PSLC-16) within the mineralized zone is 630 g/t Ag, 1.23% Cu, and 2.0% Zn, over an average true width of 2.1 meters.

Zinc Rich -- Canal Zone: Prospero's geologists mapped this new area 1,300 meters southeast of the Sta. Rosa Mine during Phase I drilling in February 2010.

Hole PSLC-17 explored at shallow depth a gossan outcrop at the contact with a quartz porphyry dike. Although additional information is necessary to establish true width, hole PSLC-19, drilled from the opposite direction, suggests that the mineralized zone intersected by PSLC-17 is dipping to the south under alluvium cover, with a significant intersection of 10.88 meters and grade of 7.2% Zn; 59 g/t Ag, and 0.30% Cu.

• This includes a higher grade portion of 4.29 meters with 11.5% Zn; 96 g/t Ag and 0.40% Cu

This new zone along the southeastern border of the Quartz-Feldspar Porphyry is open in all directions and mineralization appears to be controlled by a thrust fault that places the Jurassic Casita formation above the Cretaceous Aurora limestones (see attached plan view). This intersection suggests additional potential along the eastern border of the porphyry where largely alluvium-covered outcrops of La Puerta skarn and gossan follow the trace of the fault zone over a length of 600 meters.

The Company:

• Is currently undertaking a soil sampling survey to better define targets in the southeastern and eastern borders of the Quartz-Feldspar Porphyry
• Has completed an airborne Z-TEM (z-Axis Tipper Electromagnetic System) and magnetic survey in the district
  • Interpretation of the survey is expected in June

Copper/Silver East Skarn Zone: This area to the east of the Sta. Rosa mine was first discovered in 2007. It was the primary focus of Phase I drilling in February 2010 where shallow drilling explored the copper/silver skarn. The objective of this Phase II program was to test the depth extension of the skarn and explore its possible contact with Aurora limestones, under the thrust fault that underlies the Jurassic host rocks, and where larger skarn bodies are potentially present.

In the Sta. Rosa East Skarn Zone holes PSLC-13 and PSLC-15 encountered skarn mineralization which ranges from 5.69 meters to 10.11 meters (true width) with silver grades of 57 g/t to 62 g/t and 1.6% to 2.95% combined Cu-Zn. The only deep hole drilled to date, PSLC-18, encountered skarn with weakened mineralization. The average grade of the full width versus selected hangingwall and footwall widths of the skarn zone are shown in the longitudinal section.

A sufficient number of holes have been drilled in the Sta. Rosa East Skarn Zone to allow calculation of a preliminary resource. Deeper drilling is required to reach the Aurora limestones.

The results are as follows:

The results of this drill program further support district metal zoning with silver grades increasing to the west in the Sta. Rosa mine area. Follow-up drilling is anticipated to continue:

• Exploring the Sta. Rosa mineralized zone under the jasperoid-bearing limestones and at depth (see attached longitudinal section)
• The new Canal Zone definition , and
• Extend the Sta. Rosa East Skarn copper/silver zone further east and at depth, and
• Test Z-TEM results after definition with an IP survey.

Tawn Albinson, M.Sc., the President of the Company, is a Qualified Person, as defined in NI 43-101, and is responsible for the technical content of this press release and quality assurance of the exploration data and analytical results.

Quality Control

Prospero has a quality control program to ensure best practices in the sampling and analysis of all drill core. Samples were collected by Company employees and are shipped in sealed bags to ALS-Chemex Laboratory preparation facilities in Guadalajara, Hermosillo or Chihuahua City (Certification ISO 9001). Shipments include intermittent standards and blanks. Sample pulps are shipped to ALS-Chemex Laboratories in North Vancouver, B.C. for analysis. All samples were assayed by multielemental ME-ICP41, and gold by ICP21 (Inductively Induced Plasma-Atomic Emission Spectroscopy) which consists of a 30 gram fire assay with an ICP-AES finish. Gold values in excess of 10 g/t were re-analysed by a 30 gram fire assay and a gravimetric finish (Code Au-GRAD21). Silver, lead, zinc and copper values in excess of 100 ppm, 1%, 1% and 1% respectively were repeated with agua regia digestion and with ICP-AES (Code OG46).

About Prospero Silver Corp.:

Prospero is a Canadian resource company with the majority of its staff based in Mexico and who work for its wholly owned subsidiary Minera Fumarola, SA de CV (Fumarola). Prospero's objective is to quickly evaluate the properties currently optioned for their suitability to provide size potential and also their amenability to early production on all or part of an ore body. Prospero continues to acquire by staking potential projects in Mexico, some of which may be available for joint ventures.

Cautionary Statement:

This news release contains forward-looking statements within the meaning of the Canadian provincial securities laws that are not historical facts. Forward-looking statements involve risks, uncertainties and other factors that could cause actual results, performance, prospects and opportunities to differ materially from those expressed or implied by such forward-looking statements, including statements regarding future exploration plans. Factors that could cause actual results to differ materially from these forward-looking statements include, but are not limited to, variations in the nature, quality and quantity of any mineral deposits that may be located, the Company's inability to obtain any necessary permits, consents or authorizations required for its planned activities, and the Company's inability to raise the necessary capital or to be fully able to implement its business strategies. The reader is referred to the Company's public disclosure record which is available on SEDAR (www.sedar.com), including the risk factors discussed in Prospero's November 27, 2009 prospectus. Although Prospero believes that the assumptions and factors used in preparing the forward-looking statements are reasonable, undue reliance should not be placed on these statements, which only apply as of the date of this news release, and no assurance can be given that such events will occur in the disclosed time frames or at all. Except as required by securities laws and the policies of the TSX Venture Exchange, Prospero disclaims any intention or obligation to update or revise any forward-looking statement, whether as a result of new information, future events or otherwise.

To view the maps accompanying this press release please click on the following link: http://media3.marketwire.com/docs/PSL0517.pdf