The Marsh Grassbird Locustella pryeri is an uncommon songbird endemic to East Asia. Suitable nestsite selection can minimize nest loss, especially for opencup and ground nesting passerines. We located and monitored 66 Marsh Grassbird nests during 2004–2006 in Zhalong National Nature Reserve, northeast China, to identify characteristics of preferred nest sites. Marsh Grassbird nested mainly at sites with dense vegetation cover, high undergrowth and dry standing reed stalks, as well as small shallow ponds or rivers. Nests were more successful when they were placed higher above ground in patches with greater litter thickness. Predation and flooding were the leading causes of nest failure, accounting for at least 33 and 25 % of 24 nests lost, respectively. We advocate retention of some unharvested reed patches and implementation of irrigation strategies that avoid increasing water levels during the breeding period(May–July) of Marsh Grassbirds. Suitable nestsite selection can minimize nest loss, especially for opencup and ground nesting passerines. We located and monitored 66 Marsh Grassbird nests during 2004-2006 in Zhalong National Nature Reserve, northeast China , to identify characteristics of preferred nest sites. Marsh Grassbird nested mainly at sites with dense vegetation cover, high undergrowth and dry standing reed stalks, as well as small shallow ponds or rivers. Nests were more successful when they were placed above ground in patches with greater litter thickness. Predation and flooding were the leading causes of nest failure, accounting for at least 33 and 25% of 24 nests lost, respectively. We advocate retention of some unharvested reed patches and implementation of irrigation strategies that avoid increasing water levels during the breeding period (May-July) of Marsh Grassbirds.