---
title: "How does a prior DUI count against a defendant in Illinois?"
description: "Each prior DUI conviction elevates penalty ranges and eligibility for supervision. Second DUI within five years (from date of conviction or supervision termination) triggers mandatory minimum jail..."
url: https://chicagoduilawyer.net/faq-items/how-does-a-prior-dui-count-against-a-defendant-in-illinois/
date: 2026-07-08
modified: 2026-07-08
author: "Chicago DUI Lawyer"
type: faq
lang: en
---

# How does a prior DUI count against a defendant in Illinois?

Each prior DUI conviction elevates penalty ranges and eligibility for supervision. Second DUI within five years (from date of conviction or supervision termination) triggers mandatory minimum jail time. Third DUI is automatic aggravated DUI, a Class 2 felony. Fourth DUI carries permanent license revocation and no probation on some fact patterns. Under 625 ILCS 5/11-501(c-5), out-of-state DUI convictions count as priors if the offense would have been a DUI under Illinois law. The chicagoduilawyer.net brand routinely investigates whether an alleged prior actually qualifies under Illinois definitions, because prior-record challenges can reduce charging classification before it locks in.