May 5, 2011 – Vancouver, BC: Riverside Resources Inc. ("Riverside" or the "Company") (TSX-V: RRI) is pleased to announce that multiple 300 g/t silver and up to 5 g/t gold intervals were discovered through the mechanical trench sampling program at the Peñoles Project in Durango, Mexico. These results are the beginning of a major exploration push on the property that is under a letter agreement to option with Sierra Madre Developments Inc. (“Sierra Madre”). Highlighted trench results at the Jesus Maria target returned 22 m at 1.08 g/t Au, 224 g/t Ag, 2.5% Pb, and 1.7% Zn. These results are encouraging for Riverside as this trench is above the Jesus Maria drill target and along strike from previous mining. A second interval of 8.3m returned 1.68 g/t Au, 144 g/t Ag, 2.4% Pb and 2.2% Zn along strike showing further surface mineralization that will be tested by near term drill testing. The work at Jesus Maria reported gold values ranging from 1.4 meters returning greater than 1g/t Au. The silver values from the vein system at Jesus Maria were also very encouraging with results ranging from 7.8g/t to 572g/t, including 19 of the 34 samples returning greater than 100g/t Ag.

The trenching program completed at the San Rafael vein system returned gold-silver-lead-zinc (Au-Ag-Pb-Zn) values and alteration with relative shallow mineralization textures that are consistent with an upper level for a vein system interpretation. This could indicate that higher grades could be found at depth and indeed they have been mined from the San Rafael structure. San Rafael trenching returned 9.4m at 0.25 g/t Au. Several intervals from the trenching program returned zones of gold mineralization surrounded by widespread haloes with trace element mercury, antimony and arsenic along with anomalous values of lead and zinc. These geochemistry results are favorable indications for the possibility that a preserved mineralized zone could be present at depth.

President John-Mark Staude stated “mineralization at the surface can now be more adequately traced and the veins appear to be peaking out and showing the uppermost zones for Au-Ag-Pb-Zn-Cu drill targets.”

Further Property and Exploration Program Details

The Peñoles Project is a 350 square km concession located in Durango, Mexico. This large land package hosts a diversity of deposit types and multiple target zones including El Capitan, Capitan Hill, El Tubo, San Rafael and Jesus Maria. The recent trench results at Jesus Maria returned individual samples that reached values of up to 5 g/t gold and values over 550 g/t silver. The high Ag correlates with high Pb as some of the Ag appears to be associated with galena mineralization. The quartz vein system appears to be polymetallic with zinc samples exceeding 8% Zn. Mine dump samples gave assays of over 500 g/t Ag and 10% combined Pb – Zn, which was presented in a full technical report that Riverside filed on Sedar.com.

An initial test survey using Geotech’s VTEM system was conducted over the Capitan Hill and Jesus Maria zones and the structures show up nicely providing additional information to help focus an upcoming drill campaign that will be funded by Sierra Madre. Further work using airborne geophysics is anticipated to be progressed on the project.

Riverside and Sierra Madre signed a letter agreement on March 4, 2011 to jointly develop the Peñoles Project, and Sierra Madre is now awaiting TSX approval of the deal terms. For more detailed information on each of the target zones, maps and figures visit the Riverside website at www.rivres.com or call our offices to speak with our corporate communications team.

Amendment to Previous News Release

On March 7, 2011 Riverside announced its agreement to option the Peñoles Project to Sierra Madre Developments Inc. Riverside incorrectly stated the required exploration expenditures as $4,500,000. Sierra Madre must incur aggregate exploration expenditures of $3,000,000 within 24 months of the effective date, not $4,500,000. This figure was correctly reported in the Company’s Material Change Report filed on Sedar and has since been adjusted to reflect the accurate amount across all corporate materials.

The scientific and technical data contained in this news release has been prepared under the supervision of Mark J Pryor, Pr.Sci.Nat., an independent qualified person to Riverside Resources, who is responsible for ensuring that the geologic information provided in this news release is accurate and acts as a "qualified person" under National Instrument 43-101 Standards of Disclosure for Mineral Projects

About Riverside Resources:

Riverside is a well-funded prospect generation team of focused, proactive gold discoverers with the breadth of knowledge to dig much deeper. The Company currently has approximately $10,000,000 in the treasury and fewer than 34,000,000 shares issued. The Company’s model of growth through partnerships and exploration looks to use the prospect generation business approach to own resources, while partners share in de-risking projects on route to discovery. Additional property information on the Company’s projects can be found on the Riverside Resources Inc. website at www.rivres.com.