Coolidge v. New Hampshire, 403 U.S. 443 (1971), was a United States Supreme Court case dealing with the Fourth Amendment and the automobile exception.

Pamela Mason, a 14-year-old from Manchester, New Hampshire, placed an advertisement in the window of a local merchant offering her services as a babysitter.

Justice Stewart's opinion held that the warrant authorizing the seizure of Coolidge's automobile was invalid because it was not issued by a "neutral and detached magistrate."

The court noted that although the "automobile exception" exists, "the word 'automobile' is not a talisman in whose presence the fourth amendment fades away and disappears...".

Without their crucial evidence, the state negotiated a plea bargain by which Coolidge agreed to plead guilty to a second-degree murder charge with a sentence of 19–25 years.