Staromaynsky District () is an administrative and municipal district (raion), one of the twenty-one in Ulyanovsk Oblast, Russia. It is located in the northeast of the oblast. The area of the district is . Its administrative center is the urban locality (a work settlement) of Staraya Mayna. Population: 18,132 (2010 Census); The population of Staraya Mayna accounts for 36.0% of the district's total population.