Federal regulations under 49 CFR §391.41 list the medical conditions that disqualify a driver from operating a commercial motor vehicle in interstate commerce. The list isn't long, but the conditions on it are absolute — and several have federal "exemption" programs that let qualifying drivers regain CDL eligibility.
Vision
Distant visual acuity of at least 20/40 (corrected) in each eye and binocularly; horizontal field of view of at least 70 degrees in each eye; ability to recognize standard traffic-signal colors. Drivers who cannot meet the in-each-eye requirement (typically due to monocular vision) may apply for the FMCSA Vision Exemption.
Hearing
Must hear a forced whisper at a distance of 5 feet (with or without a hearing aid) or pass an audiometric test with average hearing loss of no more than 40 decibels at 500, 1,000, and 2,000 Hz in the better ear. Hearing aids are permitted.
Diabetes
Insulin-dependent diabetes mellitus historically disqualified drivers from interstate operation. Since 2018 the FMCSA Diabetes Exemption Program allows insulin-using drivers who meet specific glycemic control criteria (no severe hypoglycemic events in the past 5 years; A1C below 10) to operate interstate. Non-insulin-treated diabetes is generally not disqualifying.
Seizures and epilepsy
A diagnosed history of epilepsy or any seizure disorder is generally disqualifying. The FMCSA Seizure Disorder Exemption Program is available for some applicants who have been seizure-free for at least 8 years off all anti-seizure medication (or 4 years off if the seizure was a single isolated event).
Cardiovascular
Acute myocardial infarction, congestive heart failure, certain dysrhythmias, and recent cardiac surgery require a waiting period and clearance by a cardiologist before re-certification. Many cardiovascular conditions are not absolute disqualifications but require shortened (12-month or 6-month) certification cycles.
Substance abuse
Current substance abuse diagnosis or current use of any Schedule I controlled substance is permanently disqualifying. A documented history of substance abuse with at least 12 months of demonstrated sobriety and a return-to-duty evaluation under the Drug & Alcohol Clearinghouse process is generally not disqualifying. Read our Clearinghouse guide.