The two investigated plants, sweet marjoram (Origanum majorana L.) and sweet basil (Ocimum basilicmum L.) plants are considered the most important medicinal and aromatic plants. They are infested with many mites specially, the Tetranychus urticae Koch during growing season which cause considerable damage in the crop under Egyptian conditions. The present study was conducted during 2014 & 2015 seasons for sweet marjoram and sweet basil plant species at Giza governorate to survey the mite infesting these two crops at both governorates, the population fluctuations of the most important key mite and their relation to the a biotic factors (Mean temperatures & mean relative humidity as well as their associated predator, Neoseiulus californicus as biotic factor. Survey of mite species T, urticae (larvae, nymphs & adults) and predator species were recorded onsweet marjoram and sweet basil at Giza governorate. These factors gave different correlations with the population activity at Giza governorate and both host plants. We present the results of a two-year study on the population dynamics of T. urticae, as well as the association between weather parameters and the seasonal population trends of T. urticae. The objective of the present study was to find out the cause of mite outbreaks under the different climate condition and its predator effect as biotic agent.