In the late eighteenth century, the working class was in constant struggle to gain the 8-hour work day. Working conditions were severe and it was quite common that people has to work for 10 to 16 hour days in unsafe conditions. Death and injury were commonplace at many work places. As early as the 1860's, working people agitated to shorten the workday without a cut in pay, but it wasn't until the late 1880's that organized labor was able to garner enough strength to declare the 8 hour workday. This proclamation was without consent of employers, yet demanded by many of the working class.

In 1884, the Federation of Organized Trades and Labor Unions passed a resolution stating that eight hours would constitute a legal day's work from and after May 1, 1886. The resolution called for a general strike to achieve the goal, since legislative methods had already failed. With workers being forced to work ten, twelve, and fourteen hours a day, rank-and-file support for the eight-hour movement grew rapidly, despite the indifference and hostility of many union leaders. By April 1886, 250,000 workers were involved in the May Day movement. 

The heart of the movement was in Chicago, organized primarily by the anarchist International Working People's Association. But on May 3, 1886, police fired into a crowd of strikers at the McCormick Reaper Works Factory, killing four and wounding many. Anarchists called for a mass meeting the next day in Haymarket Square to protest the brutality. A bomb thrown by an unknown person at a labor rally in Chicago's Haymarket Square killed one policeman; authorities rounded up whom they considered to be the leaders of the local labor movement and put them on trial. Mother Jones said of the incident: "The workers asked only for bread and a shortening of the long hours of toil. The agitators gave them visions. The police gave them clubs." 

Spurred by a resolution from the American Federation of Labor (AFL) and the International Socialist Congress, this day saw parades not only in American cities but simultaneous demonstrations throughout the European industrial centers and in Havana, Cuba. The common theme was the demand for guaranteed eight-hour workdays, and to raise awareness of the common class struggle existing in all countries. From that time on, May Day became an annual gathering of the working class in industrial countries. 

In the US, Labor Day was started in September of 1882, and quickly became an official holiday at the same time May Day spread throughout the world. Labor Day is a time to celebrate the contributions American workers had given their country, unlike May Day events, which focused on the international class struggle. It remains a patriotic holiday, and compared to the first May Day demonstrations, Labor Day is recognized by relatively staid parades and speeches. 

May Day is still celebrated by socialist, communist, and labor organizations in America. May Day 1998 saw a small demonstration in Olympia against the Washington State "anarchy and sabotage" statute, which in 1919 made it illegal for anyone to display banners, flags, or emblems that are perceived to advocate subversion of the US Constitution, federal or state laws. In Seattle, hundreds marched for unionization and better pay for child-care workers, and on the UW campus over 500 participated in the first annual Teach-In on Globalization and Democracy, subtitled "Do Free Markets make Free People?"