A study on comparative efficacy and in vitro activity of fresh cow urine and cow dung for controlling Sclerotinia rot caused by Sclerotinia sclerotiorum of cucumber was carried out following mycelial growth inhibition test, treated and untreated sclerotia with these organic matters at different days of incubation. Results showed that cow urine suppressed more effectively the mycelial growth even after 5 days of incubation in comparison to cow dung. The highest inhibition 75.9% of mycelial growth was recorded in cow dung potato dextrose agar(CUPDA) after 3 days of incubation and least 22.7% was in cow dung potato dextrose agar(CUPDA) after same days of incubation. Mycelial growth from sclerotia of S. sclerotiorum was also influenced by PDA medium mixed with cow urine and cow dung. After 6 days of incubation in CUPDA mycelial growth was only 12.9 mm whereas in CDPDA and PDA the corresponding growth at the same time were 65.8 mm and 80.0 mm. Treated sclerotia of the selected fungus with cow urine had a very effective role on suppression of mycelial growth than that of untreated one. No mycelial growth was observed up to 4 days in treated sclerotia with cow urine. After 5 days only 0.9 mm mycelial growth was measured in treated sclerotia, while in case of untreated sclerotia the growth was 42.6 mm. Application of cow urine and cow dung on growing plants inoculated with the pathogen at different concentrations also proved their inhibitive effects.