In her eighties and nineties, Mother Jones wanted to continue fighting, but her body was aging much faster than her mind. She regretted that she could not help the workers more, but was happy to hear about certain political developments, such as the creation of the Farmer-Labor Party. Previously, Mother Jones did not deal much with politics, which she felt betrayed the interests of labor. In addition, she also accused some notable labor leaders of disregarding the needs of workers while prioritizing the needs of businessmen. Mother Jones felt that the Farmer-Labor Party answered the need of a workers' party, and she addressed the assembly at the Party's convention.
During the 1920s, Mother Jones traveled to Mexico, where she was greeted by enthusiastic workers. The president of Mexico, Alvaro Obregon, welcomed her to the convention of the Pan-American Federation of Labor. Mother Jones knew how important it was to unify all workers in the labor struggle, particularly since she had dealt with many immigrants who faced constant oppression wherever they went to work. A hemispheric federation would unify workers and make them more powerful over a greater geographical area. Mother Jones was so pleased with her first trip to Mexico that she returned shortly after and stayed for two months.
Upon her return to the United States in 1922, Mother Jones was bedridden by rheumatism. Two old friends, Terence and Emma Powderly, took care of her in their home. However, after a month, Mother Jones was already feeling better and began planning a trip to Illinois. After visiting John Walker, her fellow organizer in West Virginia, she left for Chicago, where Molly Field Parton awaited her. Parton had agreed to work with Mother Jones on her autobiography. Soon, Mother Jones grew tired and frustrated with the work involved in writing her autobiography. She enlivened herself by participating distantly in strikes, even though she no longer had the energy to be an active organizer. However, she did have the energy to address workers at least one more time. During a dressmakers' strike, Mother Jones exhorted and encouraged the workers who were tormented and harassed by arrests, injunctions, and blacklists.
Mother Jones's autobiography was published in 1925. Although the book was accused of containing factual inaccuracies, it was written when Mother Jones was old, and survived more as an emotional testament to the values that she worked for than as a factual analysis of the past. In 1924, Mother Jones returned to live with Terence and Emma Powderly. That summer, Terence died, and Mother Jones was left alone with Emma. She stayed with Emma Powderly, but frequently went to live in California with a Mrs. Schmidt. There, the warm climate improved her rheumatism, although nothing could quite cure it. Eventually, Mother Jones's rheumatism became so bad that her friends could no longer care for her, and she went to live with a retired miner and his family in Washington, where she died on November 30, 1930. Mother Jones was buried in the Miners Cemetery in Mount Olive, Illinois. This cemetery was a union-owned cemetery, and Mother Jones had asked to be buried near the "Virden Martyrs," the men killed by company detectives during a strike at the Virden mines. Workers flocked to her funeral, and her casket was carried by representatives of different unions. A choir of miners sang the mass.