The study was carried out in Barmer district of Rajasthan to analyze economics of Isabgol production and constraints faced by farmers. The primary data were collected from total sample of 80 farmer’s respondents. The study reveals that total cost of cultivation was higher ` 38407.69 per hectare on large farm, followed by ` 34132.15 on medium and ` 31281.96 on small farm and ` 34607.27 per hectare on overall farm. The cost of cultivation increases as farm size increase. It is observed from the result of F test p value is .001 which shows that there is statistically significant difference in cost of cultivation of Isabgol on different farm size category. The different cost on the basis of cost concept (Cost A1, A2, B1, B2, C1, C2 and C3) of Isabgol cultivation per hectare was calculated. The cost of production was found lower on large farm it was found to be ` 5053.64 per quintal followed by ` 5094.35 per quintal on medium farm, ` 5128.19 per quintal for small size farm which was found highest and ` 5092.06 per quintal for overall farm size. Farm business income, family labor income and farm investment income of Isabgol cultivation was found highest on large farm. The benefit cost ratio was found at 1.63 for overall farm size and was found to be 1.68 for large farm, 1.64 for medium farm and 1.63 for small farm. Crop damage by pest and diseases are the most important constraints faced by farmers in Isabgol production.