Filed under Rule 424(b)(3) of the Securities Act of 1933,
relating to Registration No. 333-123193

Prospectus Supplement No. 1
to Prospectus Dated April 7, 2005
of

MINDSPEED TECHNOLOGIES, INC.

Relating to

$46,000,000
3.75% Convertible Senior Notes due 2009
and
Shares of Common Stock
Issuable upon Conversion of the Notes

     This prospectus supplement relates to the resale by certain selling security holders of our 3.75% Convertible Senior Notes due 2009 and the shares of our common stock issuable upon conversion of the notes.

     You should read this prospectus supplement in conjunction with the prospectus dated April 7, 2005, which should be delivered in conjunction with this prospectus supplement. This prospectus supplement is not complete without, and may not be delivered or used except in conjunction with, the prospectus, including any amendments or supplements to it. This prospectus supplement is qualified by reference to the prospectus, except to the extent that the information provided by this prospectus supplement supersedes information contained in the prospectus.

     Investing in the notes and the common stock issuable upon conversion of the notes involves risks that are described in the “Risk Factors” section beginning on page 6 of the prospectus dated April 7, 2005.

     Neither the Securities and Exchange Commission nor any state securities commission has approved or disapproved of these securities or passed upon the adequacy or accuracy of this prospectus supplement or the prospectus dated April 7, 2005. Any representation to the contrary is a criminal offense.

The date of this prospectus supplement is June 10, 2005.

Adjustment of Conversion Price

     Effective May 13, 2005, the conversion price of the notes was adjusted to $2.31 per share of common stock, which is equal to a conversion rate of approximately 432.9004 shares of common stock per $1,000 principal amount of notes. Prior to this adjustment, the conversion price applicable to the notes was $2.81 per share of common stock, which was equal to approximately 355.8719 shares of common stock per $1,000 principal amount of notes. The adjustment resulted from application of the “barrier adjustment” to the initial conversion price as described in the prospectus under “Description of the Notes — Conversion Rights — Conversion Price Adjustments.” The conversion rate is subject to further adjustment as described in the prospectus under “Description of the Notes – Conversion Rights.” As a result, the number of shares of common stock issuable upon conversion of the notes may increase or decrease in the future.

Selling Security Holders

     The table under the caption “Selling Security Holders” beginning on page 61 of the prospectus is hereby supplemented and amended by updating information as to the selling security holders identified in the following table. The following table sets forth certain information concerning the principal amount of notes beneficially owned by each selling security holder and the number of shares of underlying common stock that may be offered from time to time by each selling security holder pursuant to the prospectus and this prospectus supplement. The information in the following table is based on information provided to us by or on behalf of the selling security holders on or before June 10, 2005. We have assumed for purposes of the table below that the selling security holders will sell all of their notes and common stock issuable upon conversion of the notes pursuant to the prospectus and this prospectus supplement, and that any other shares of our common stock beneficially owned by the selling security holders will continue to be beneficially owned by them. We have also assumed for purposes of the following table that unnamed holders of notes, or any future transferees, pledgees, donees or successors of or from any such holder, do not beneficially own any common stock other than that issuable upon conversion of the notes.

     Information about the selling security holders may change over time. In particular, the selling security holders identified below may have sold, transferred or otherwise disposed of all or a portion of their notes since the date on which they provided to us information regarding their notes. Any changed or new information given to us by or on behalf of the selling security holders will be set forth in supplements to the prospectus or amendments to the registration statement of which the prospectus is a part, if and when necessary.

     Except as set forth in the footnotes below, none of the selling security holders has, or within the past three years has had, any position, office or other material relationship with us or any of our predecessors or affiliates.

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