The Himalaya harbors a large number of plant endemics but information on their genome size is largely lacking. This study aims to fulfill this gap by reporting genome sizes for 8 endemic Himalayan plant species (Impatiens devendrae Pusalkar, Impatiens scabrida DC., Impatiens sulcata Wall., Geranium robertianum L., Geranium wallichianum D.Don ex Sweet, Thalictrum cultratum Wall., Thalictrum elegans Wall. ex Royle, Thalictrum foliolosum DC.) from the Western Indian Himalayan state of Uttarakhand. The study involved collecting leaf tissues from each of the 8 plant species, chopping, staining and estimating nuclear DNA content using CyFlow Cube 8 flow cytometer with 532 nm laser light source and an orange-red fluorescence emission (>590 nm). The CyFlow Cube 13 programme was utilised to obtain the median fluorescence value from PI-stained G0/G1 (quiescent phase/first growth phase) nuclei, devoid of cellular debris. The DNA 2C value of each sample was then estimated by comparing the median fluorescence intensity values of both sample and standard (Solanum lycopersicum L.) using the standard scientific formula. The highest DNA 2C-values were observed in Geranium, which ranged from 5.29 ± 0.02 pg to 2.49 ± 0.02 pg. The genome size of Impatiens species varied from 1.49 ± 0.08 pg to 3.14 ± 0.04 pg while the three species of genus Thalictrum had nearly similar genome sizes varying between 1.53 ± 0.01 pg to 1.96 ± 0.06 pg. The coefficient of variation among nuclei varied from 3.52 % to 5.38 % with 103 to 1811 numbers of stained nuclei. The results and framework presented in the current study can serve as a template for future studies that attempt to estimate the genome sizes of endemic plant species in the Himalaya, a global biodiversity epicentre and one of the least studied biodiversity hotspots of the world.