Onion (Allium cepa L.) is one of the important commercial vegetable crops grown in India. The present study was conducted in Nuh district of Haryana on the basis of highest production of onion among other districts of the state. The block named Tauru was selected for sampling and a total of thirty onion farmers from various villages in this block were selected randomly. The primary data for the agriculture year 2017-18 were collected by personal interviews of the selected farmers with the help of specially designed schedule. The results of the study revealed that the major problems faced by the onion farmers in production were observed high cost of pesticide (93.33%), lack of knowledge about recommended fertilizer doses (86.67%), high cost of fertilizer (83.33%), lack of knowledge about the control measures for various pests and diseases (83.33%), difficulty in identifying the pests and diseases (80.00%) and lack of knowledge about seed/seedling treatment (76.67%). As for as marketing of onion is concerned, 83.33 per cent of respondents opined that high cost of transportation, absence of minimum support prices (83.33%), existence of large number of intermediaries in marketing process (83.33%) and too much fluctuation in prices (80.00%). The problems related to processing expressed by onion growers 80.00 per cent of the respondents reported the problem of technical manpower, higher charges of power and fuels (73.33%), fluctuation in raw material and procurement (73.33%) and lack of good quality packaging material (66.67%).