The 1986 Monaco Grand Prix was a Formula Onemotor race held at Monaco on 11 May 1986. It was the fourth race of the 1986 Formula One World Championship. The Monaco circuit had been modified from the year before: the chicane after the tunnel now had three turns and was renamed the Nouvelle Chicane. The end result was that the chicane was slowed considerably from the old left-right flick it was previously, plus it added 16 metres to the circuit length.
Patrick Tambay had a spectacular accident when he and Martin Brundle tangled at Mirabeau, and Tambay's Lola-Ford went right over Brundle's Tyrrell-Renault, caught six feet of air and barrel-rolled into the protective Armco right next to some spectators, and in the process almost went over the Armco into a bar next to the track. Luckily the Lola landed upright and Tambay was able to walk away from the accident unscathed.
This was also the last Grand Prix for Italian Elio de Angelis, before his fatal testing accident at Paul Ricard three days later.
This was the last Monaco Grand Prix where only 20 cars would be allowed to start. From the 1987 race the available grid size would be the same 26 cars as every other race.