AirHint found the following cheapest one-way flights from Chicago (ORD) to Madrid (MAD) in September 2025 (see full year).

One-Way flights

28 Sep	jetBlue
08 Sep	Icelandair
07 Sep	Icelandair
22 Sep	Icelandair
16 Sep	Spirit Airlines
25 Sep	Spirit Airlines
13 Sep	Spirit Airlines
17 Sep	Spirit Airlines
11 Sep	Spirit Airlines
20 Sep	Spirit Airlines

Also check the deals for return flights from Chicago to Madrid in September.

The deals are updated regularly. The prices may go up as tickets are purchased by other travellers. Only the cheapest flights are offered. Select a price to book and secure these cheap prices.

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Cheapest one-way flights from Chicago to Madrid in September from $245

One-Way flights