Find the most convenient Department of Motor Vehicles (DMV) office in the state where you hold your license. For example, if you got your license in Texas, then you should visit a Texas DMV office, even if there is a closer office in another state.
Inform the staffer at the DMV that you wish to renew your CDL. Provide them with your old CDL, valid regular driver's license, Social Security card, proof of residence and insurance documentation for the commercial motor vehicle (CMV) for which you are renewing the license. Documents required vary among states. For many, you will not need proof of residence, for example.
Complete all forms and examinations. This can include a basic vision and eyesight test, which you will have been required to pass when you first applied for your CDL. Pay the relevant fee for your renewal which, for example, costs $117 in Washington, D.C. (as of March 2011). A renewed DC license is valid for five years.
Undergo any examinations for endorsements that you have on your license. For example, you must retest to gain a renewed class H (hazmat) endorsement in nearly every state. Determine whether you need extra endorsements, such as a class S, which enables you to drive a school bus. Complete any written and practical examinations to gain endorsements additional to your renewed CDL. Renewing an endorsement in Idaho, for example, costs $15 per endorsement (as of March 2011).