Aims: To assess the contrast sensitivity (CS) in different stages of primary open angle glaucoma and to correlate it with the severity (mild, moderate & severe) of glaucoma. Materials and Methods: This prospective randomized study was conducted at Sapthagiri institute of medical sciences and research centre, Bangalore between June 2017 & December 2017. A total of 100 eyes of 55 individuals aged 25-80 years diagnosed with POAG were enrolled in this prospective study. Selected subjects underwent detailed ophthalmic examination including ocular history, slit lamp examination, objective & subjective refraction (if required) to obtain best corrected visual acuity (BCVA) on Snellen visual acuity chart and dilated fundus evaluation using indirect ophthalmoscopy. Eyes with clear media and ≥BCVA 6/60 were included and contrast sensitivity was measured using Pelli Robson chart at 1 meter distance. HFA report of included subjects were collected from Glaucoma department to classify them in to mild, moderate and severe groups according to their visual field findings (pattern deviation of HFA report). Classification was done according to International statistical classification of disease and related health problem (ICD 10). One way ANOVA and t-test was used to analyze the data. Results: There was 36% mild, 26% moderate and 38% severe cases of POAG classified according to ICD 10. The mean value of contrast in mild, moderate and severe POAG was 1.4341, 1.3267 and 1.1326 respectively. An analysis of variance tested whether there were significant difference in contrast sensitivity among mild, moderate and severe POAG. Results indicated that these means differed significantly p < 0.01. Hence there is gradual decrease in CS with the severity of glaucoma. Conclusion:There was decrease in contrast sensitivity with the severity of POAG. Thus the contrast sensitivity testing should be made mandatory in evaluating POAG patients which could help in screening/diagnosis (early detection) and to assess the progression of the disease as well as response to the treatment.