Two host planst, Cucumber, Cucumis sativus L. and kidney bean Phaseolus vulgaris L.were sown at Horticultural Research Station at Kaha region, Qalubiya Governorate, Egypt to determine the host preference to certain pests including, thrips Thrips tabaci (Lind.), aphids, whitefly, Bemisia. tabaci (Genn.) and the two spotted spider mite, Tetranychus urticae (Koch) and its relationship with climatic factors and anatomical characters during two successive seasons 2011 and 2012. The results indicated that the infestation rate of B. tabaci and T. tabaci increased on cucumber leaves more than kidney bean. On the contrary, kidney bean was suitable host to development of aphid and T. urticae. The incidences of the four studied pests were significant and positive correlated with maximum temperature and maximum relative humidity. While, the population density of these pests positively correlated and non-significant with minimum temperature. On the contrary, the minimum relative humidity had negative and non-significant effect on the two host plants. In the two host plants, anatomical characters of play an important role in the infestation rates of the previously mentioned pests. Kidney bean had the thickest layers of upper& lower epidermis and spongy tissues and the thinnest layer of palisade tissue. On the other hand, cucumber leaves had the thickest layer of palisade tissue. The population density of all pests had positive relationship and significant with palisade and spongy layers. While, this relation was significantly negative with upper and lower epidermis. i.e., infestation rates of all studied pests increased by increasing the thickest layers of palisade and spongy tissues and decreased by increasing the thickest of upper and lower epidermis. The amount of variability that could be attributed to the combined effect of the tested weather factors and anatomical characters on the four studied pests was more than 60%.