This research aimed to inspect the impacts of severe parasitic plants (Orobache spp.) on grain yield, some quality characteristics, marketing price and profitability loss of red lentil in the major lentil growing area of south-east Anatolia. Farmer field trials were carried out in two neighbouring fields planted with Yerli Kırmızı (landrace) and Firat-87 varieties of lentil employing a split-plot experimental design in the Yollar basi location of Viransehir in the 2018–2019 crop growing season. Lentil varieties were placed into main plots and the broomrape infestations (i.e. 0, 5, 10, and 15 plants m^-2) in the subplots respectively. Grain yield, hectolitre weights and 1000-kernel weights and protein contents (%) were scored. All grain samples were presented to randomly chosen grain purchasers in the local commodity market and marketing price offers were scored respectively. Results showed that broomrape infestation from zero to 15 broomrapes m^-2 reduced the grain yield significantly from 2033.33 kg ha^-1 to 833.33 kg ha^-1 by 59%. Although being non-significant, Firat-87 (1512, 5 kg ha^-1) was found to be higher yielding than Yerli Kırmızı (1325 kg ha^-1). Regression equations between grain yield reductions vs. broomrape infestation ratios turned out to be significant and reliable with high coefficients of determinations for both varieties. Some visual purchasing criteria such as hectolitre and 1000-kernel weights were not affected seriously. Purchasers offered very similar marketing prices for pulse grains with all severity levels. The economic loss was huge ($555 ha^-1). Regression equations derived from grain yield vs. infestation densities were found to be reliable with high coefficients of determinations and can be perfectly used for yield estimates under various levels of broomrape infestations. It was concluded that an infestation over 15% might result in a disastrous yield loss in lentil production. Therefore, some agronomic measures must be taken quickly.