Yanmar Stadium Nagai, Athletic stadium in Nagai Park, Osaka, Japan

Yanmar Stadium Nagai is an oval athletics stadium in Nagai Park, Osaka, with a 400 m nine-lane track around a 107 by 71 m natural grass field. Its single-tier stands seat 47,853 under two arched roofs that carry integrated floodlights, and a dark scoreboard stands above one end.

Nagai Stadium opened in 1964 on the site of the former Osaka Central Velodrome, with an initial capacity of 23,000, and hosted football matches of the 1964 Tokyo Olympics. A full reconstruction began in September 1992 for the 1997 National Sports Festival, was completed in May 1996, and raised capacity to 50,000. The venue then hosted three matches of the 2002 FIFA World Cup and the 2007 World Championships in Athletics.

The stadium has been the start and finish of the Osaka International Ladies Marathon since 1982, run in late January or early February; the 1995 edition was cancelled after the Great Hanshin earthquake. The course also served as the finish for the national high school and university women's ekiden relays.

Tsurugaoka Station on the JR-West Hanwa Line is a 3-minute walk away; Nagai Station, served by the Hanwa Line and the Osaka Municipal Subway Midosuji Line, is 5 minutes on foot. Harinakano Station on the Kintetsu Minami Osaka Line is about 20 minutes on foot. City buses stop at Subway Nagai and Nagaikoen-kitaguchi.

The naming rights deal, signed on 1 March 2014, covered two Nagai Park venues for a combined annual fee of 100 million yen (excluding tax): this stadium became Yanmar Stadium Nagai and the neighbouring second stadium Yanmar Field Nagai. Yanmar, a diesel engine and machinery manufacturer, is also the parent company of Cerezo Osaka. The first match under the new name was Cerezo's J1 opener against Sanfrecce Hiroshima; the official naming ceremony followed on 12 April 2014 with the Osaka derby against Gamba Osaka.