In this work, we evaluated the ovicidal activity and the deleterious effects of cashew (Anacardium occidentale) nut shell oil and its fractions on the development of Musca domestica and Chrysomya megacephala, important vectors of several diseases. The insecticidal effects of this plant were also measured on the first and second instar larvae of Anticarsia gemmatalis and Spodoptera frugiperda, soy and maize pests, respectively. The fly eggs and the crop pest insect larvae were exposed to the cashew (Anacardium occidentale) nut shell liquid (CNSL) and its fractions: technical CNSL, anacardic acid, cardanol and cardol. The results show that the cardol fraction, for both species of flies, presented the lowest lethal concentration with LC50 of 80.4 mg/L for M. domestica and 90.2 mg/L for C. megacephala. For the mortality of the larvae of A. gemmatalis and S. frugiperda, the most effective fraction was anacardic acid with LC50 of 295.1 mg/L and 318.4 mg/L, respectively. In all species, the mortality rate of the commercial compounds (cypermethrin 600 mg/L and temephos 2 mg/L) was higher than that of the evaluated compounds. Despite this, the results obtained suggest their potential in field trials, once the fractions of A. occidentale presented high mortality at low lethal concentrations in laboratory conditions, with the possibility of integrated use in the control of disease vectors and agricultural pests, employing ecofriendly compounds.