EXHIBIT 99.6 ------------ MCLEODUSA INCORPORATED OFFER TO EXCHANGE ITS 8 3/8% SENIOR NOTES DUE MARCH 15, 2008 WHICH HAVE BEEN REGISTERED UNDER THE SECURITIES ACT OF 1933 FOR ANY AND ALL OF ITS OUTSTANDING 8 3/8% SENIOR NOTES DUE MARCH 15, 2008 TO OUR CLIENTS: Enclosed for your consideration is a Prospectus, dated , 1998 (the "Prospectus"), and a form of Letter of Transmittal (the "Letter of Transmittal"), relating to the offer (the "Exchange Offer") of McLeodUSA Incorporated (the "Company") to exchange its 8 3/8% Senior Notes due March 15, 2008, which have been registered under the Securities Act of 1933 (the "1998 Exchange Notes"), for any and all of its outstanding 8 3/8% Senior Notes due March 15, 2008 (the "1998 Senior Notes"), upon the terms and subject to the conditions described in the Prospectus and the Letter of Transmittal. The Exchange Offer is being made in order to satisfy certain obligations of the Company contained in the Registration Agreement dated as of March 16, 1998, among the Company, Salomon Brothers Inc, Bear, Stearns & Co. Inc., Morgan Stanley & Co. Incorporated and Chase Securities Inc. This material is being forwarded to you as the beneficial owner of the 1998 Senior Notes carried by us in your account but not registered in your name. A TENDER OF SUCH 1998 SENIOR NOTES MAY ONLY BE MADE BY US AS THE HOLDER OF RECORD AND PURSUANT TO YOUR INSTRUCTIONS. Accordingly, we request instructions as to whether you wish us to tender on your behalf the 1998 Senior Notes held by us for your account, pursuant to the terms and conditions set forth in the enclosed Prospectus and Letter of Transmittal. Your instructions should be forwarded to us as promptly as possible in order to permit us to tender the 1998 Senior Notes on your behalf in accordance with the provisions of the Exchange Offer. The Exchange Offer will expire at 5:00 p.m., New York City time, on , 1998, unless extended by the Company (the "Expiration Date"). Any 1998 Senior Notes tendered pursuant to the Exchange Offer may be withdrawn, subject to the procedures described in the Prospectus and the Letter of Transmittal, at any time prior to the Expiration Date. If you wish to have us tender your 1998 Senior Notes, please so instruct us by completing, executing and returning to us the instruction form included with this letter. THE LETTER OF TRANSMITTAL IS FURNISHED TO YOU FOR INFORMATION ONLY AND MAY NOT BE USED DIRECTLY BY YOU TO TENDER 1998 SENIOR NOTES. INSTRUCTIONS WITH RESPECT TO THE EXCHANGE OFFER The undersigned acknowledge(s) receipt of your letter and the enclosed material referred to therein, including the Prospectus and the accompanying form of Letter of Transmittal, relating to the Exchange Offer made by McLeodUSA Incorporated with respect to its 1998 Senior Notes. This will instruct you as to the action to be taken by you relating to the Exchange Offer with respect to the 1998 Senior Notes held by you for the account of the undersigned, upon and subject to the terms and conditions set forth in the Prospectus and the Letter of Transmittal. The aggregate principal amount of the 1998 Senior Notes held by you for the account of the undersigned is (fill in amount): $ ___________________________________ of the 8 3/8% Senior Notes due March 15, 2008 With respect to the Exchange Offer, the undersigned hereby instructs you (check appropriate box): [_]To TENDER the following 1998 Senior Notes held by you for the account of the undersigned (insert aggregate principal amount at maturity of 1998 Senior Notes to be tendered, in integral multiples of $1,000): $ ___________________________________ of the 8 3/8% Senior Notes due March 15, 2008 [_]NOT to tender any 1998 Senior Notes held by you for the account of the undersigned. 2 If the undersigned instructs you to tender the 1998 Senior Notes held by you for the account of the undersigned, it is understood that you are authorized to make, on behalf of the undersigned (and the undersigned, by its signature below, hereby makes to you), the representations, warranties and agreements contained in the Letter of Transmittal that are to be made with respect to the undersigned as beneficial owner. SIGN HERE Name of beneficial owner(s): __________________________________________________ Signature(s): _________________________________________________________________ Name(s) (please print): _______________________________________________________ Address: ______________________________________________________________________ Telephone Number: _____________________________________________________________ Taxpayer Identification or Social Security Number(s): _________________________ Date: _________________________________________________________________________ None of the 1998 Senior Notes held by us for your account will be tendered unless we receive written instructions from you to do so. Unless a specific contrary instruction is given in the space provided, your signature(s) hereon shall constitute an instruction to us to tender all the 1998 Senior Notes held by us for your account. 3