Reduction in niger seed yield was minimum in cv. Ootacamund (63%) due to Cuscuta infestation. Niger height and per cent Cuscuta infestation were reduced with increasing densities of Cuscuta. A density of single plant of Cuscuta m-2 caused 100% infestation to niger in 80 days; however, it was lesser at lower densities (73.7 to 74.3%). There was a reduction in niger seed yield from 55 to 99.2% with increasing densities of Cuscuta (0.258 mo2).