This article is concerned with establishing a necessary an sufficient condition for the oscillation of all solutions of the delay differential equation of the form y'(t) + p1y(t – 1) + p2y(t – 21) + p3y(t – 31) = 0, which is a special case of the generalized type of first order delay differential equation of the form y t p y t i i i n a f 1 0 , pi, i > 0. Examples to illustrate our established result are constructed and compare with result established by Hunt and York (1984).
