Three compounds isolated from non-saponified fraction of crude petroleum ether extracts of Abrus precatorius L. seeds were tested for their acaricidal activity against the females and eggs of Tetranychus urticae Koch. The role of compounds II (beta-amyrin) on the biological activity of this pest was taken in consideration. The compounds isolated include compound I (may be coumarin), beta-amyrin and mixture of sterols, all of which were toxic to both adult females and eggs of the two-spotted spider mite. B-amyrin proved to be more efficient than the other compounds tested for the toxicity of both stages. Spraying the adult females with LC25 of beta-amyrin caused a high significant reduction in the fecundity in comparison to the control. Also the viability of the resulting eggs was greatly reduced while the durations of the immature stages were unaffected.