Rice varieties of different plant heights viz. Jagannath and Gayatri (semi-dwarf), Panidhan and Tulasi (semitall) and Amulya and Champaisali (tall) along with flood-tolerante local check FR13A (semi-tall) were evaluated for submergence tolerance and yield performance under flood-prone lowland conditions. Semidwarf varieties submerged for 10 days at active tillering and/or maximum tillering showed a greater tiller mortality (26.3%) and decrease in dry matter production (29.9%) compared with semi-tall types (13.9 and 22.8%), which were submerged partially. Flash-flooding at maximum tillering caused less damage than at early tillering. The semi-tall varieties, Panidhan and Tulasi produced maximum grain yield under natural submergence (2.84-3.33 t ha^-1) as well as flash-flooding at active tillering (2.17-2.56 t ha^-1) and maximum tillering (2.18-2.72 t ha^-1). The grain yield of improved tall selections, Amulya and Champaisali was low (1.93-2.04 t ha-1) but stable (CV 4.8-5.1%) under flash-flooding The flood-resistant local check, FR13A showed a similar behaviour under flash-flooding as the tall types but produced lower grain yield (2.04-2.07 t ha^-1) than the improved semi-tall types.