A greenhouse experiment was conducted to study the efficacy of the fungi cultures filtrates of Trichoderma harzianum or T. viride at 60%, 80% and 100% concentrations in comparison with oxamyl on the control of Meloidogyne incognita infecting potato plant cv. sponta. Results indicate that the tested filtrates obviously caused remarkable increase in potato plant growth characters and significantly reduced root galling, females, and eggmasses on root system as well as number of juveniles of M. incognita per cc soil. As the filtrate concentration of the micoparasitic fungi increased from 60% up to 100% , the percentage increase of plant growth characters increased  from 7.69 to 37.7 % for shoot dry weight  as well as from 17.3 to 56.9% for fresh weight of whole plant in case of T. harzianum while the increase in case of  T. viride was recorded to be from 10.25 to 139.7% and from 13.75 to 77.33% for the former and latter criteria, respectively. T. harzianum at 100% achieved the highest percentage increase of tuber fresh weight with value of 93.3%, followed by T. viride at 100 % (66.6%)and then oxamyl (50.5%), respectively as compared to nematode alone. Moreover, oxamyl application achieved the highest percentage of increase for length of shoot plus root with value of 25 %, whereas both fungal filtrates at100% gave an equal value (10%) for this criterion. With respect to nematode development parameters, T. harzianum at the three concentrations tested surpassed those of T. viride in supressing number of galls, females, eggmasses and juveniles/ cc soil as compared to nematode alone. Oxamyl  application gave a considerable reduction percentage values of nematode development parameters tested but not exceeding  those of T. harzianum filtrate at 100% or 80% for number of females (69.5 or 69.0%) and eggmasses (69.2% or 68.7%), respectively. T. harzianum at 100% achieved the highest percentage of increase values of nitrogen (45.2%) phosphorus (98.2%) and potassium (101.0%) and recorded the highest percentage of reduction in total chlorophyll content with value of 27.62%, respectively, followed by T. viride at 100% with values of 44.5%, 105.3% 73.2% and 27.06%, respectively as compared to that of nematode alone . Oxamyl application accomplished the highest percentage reduction of total chlorophyll content value of 28.46 % comparing to nematode alone and other tested treatments.