Martensdale is a city in Warren County, Iowa, United States. The population was 467 at the 2000 census. It is part of the Des Moines–West Des Moines Metropolitan Statistical Area.
Martensdale is located at 41°22′23″N 93°44′23″W / 41.37306°N 93.73972°W / 41.37306; -93.73972 (41.373148, -93.739661), along the Middle River. According to the United States Census Bureau, the city has a total area of 0.4 square miles (1.0 km²), all of it land.
The Great Western Trail has its southern terminus in Martensdale.