Intense livestock grazing outcompetes wild ungulates in low-productivity rangelands. This is a long-standing and highly debated conservation problem globally. We examined impacts of migratory livestock grazing on Trans-Himalayan rangeland and Asiatic ibex, a wild ungulate and primary prey of the endangered snow leopard. Vegetation and ibex were sampled in an intensely grazed (livestock density 63 sheep-goat km-2) and ungrazed areas, during spring (before grazing), summer (during grazing) and autumn (after grazing). Proportionate to vegetated area, independent randomly laid 1m x 1m plots were sampled for vegetation cover and biomass estimation (Cover: NUngrazed=237; NGrazed=127; Biomass: NUngrazed=119; NGrazed=64). Ibex density and young:adult-female ratios were estimated by repeatedly sampling 17 trails using double-observer methods across both treatments for the three time periods and two consecutive years. Graminoid and herb biomass were significantly higher in ungrazed than grazed areas (ANOVA; Graminoid: FTreatment=16.05; P=<0.001; Herb: FTreatment=22.75; P=< 0.001). Overall vegetation composition was dissimilar across ungrazed and grazed areas (Morisita Index 0.18); however, palatable species composition was similar (Morisita Index 0.70). Biomass of palatable species was 2.25 times higher in ungrazed areas. Total off-take of dry forage by migratory livestock from grazed pastures (61 km2) was 10,658 kg km-2 over two months of grazing. Ibex density was 1.80-7.0 times higher in ungrazed areas in 2015, while 2.45-4.7 times higher in ungrazed areas during 2016. Ibex yearling:adult-female ratio was six times higher in ungrazed areas. Significant reduction in forage availability lowered ibex density and yearling:adult-female ratios in grazed areas, suggesting migratory livestock outcompetes ibex through exploitative competition.