The relation between the major plant nutrients, NPK and their combinations on tomato infestation with B.tabaci (Genn.), was studied in Imbaba district, Giza Governorate during 1995-1996. An obvious in­crease of this pest accompanied by decreasing in tomato yield was ob­served on the plants treated with high levels of N. (ammonium sulphate, 21% N). On the other hand, the study proved that the moderate level of N (1 50 unit) corresponding with potassium sulfate [Potasium sulfate, 60 units/K20)] and superphosphate (60 unit/P202) - in mixtures-gave low population of B.tabaci and higher level in yield.