In this article, we study a first order nonlinear delay differential equation x ′ (t) + m i=1 p i (t) f i x(τ i (t)) = 0, t ≥ t 0 , where p i (t) and τ i (t) are the functions of nonnegative of real numbers and τ i (t) are not necessarily monotone for 1 ≤ i ≤ m. Also, we present new sufficient conditions for the oscillatory solutions of this equation. Our results essentially improve the conditions in the literature. Finally, we give examples to illustrate our results.