In which year did the Institutional Revolutionary Party lose in the Presidential elections after having ruled for nearly 6 decades?

2000

Over a period of time, Plutarco Elías Calles, the founder of PRI, was able to capture the organization and thereby the government. Elections were held at regular intervals and it was the PRI that won every time. Other parties existed in name only so as to give the ruling party greater legitimacy. The electoral laws were operated in a manner so as to ensure that the PRI always won. Elections were often rigged and manipulated by the ruling party. Its rule was described as ‘the perfect dictatorship’. Finally, the party lost in the Presidential elections held in 2000. Mexico is no longer a one-party-dominated country.