Redents and their ectoparasites populations are key components of animal production farms production in Egypt and all over the world. However, their population dynamics and the factors affecting their abundance are still not well understood. The seasonal variations during  the activity periods of Rattus rattus frugivorous and Rattus norvegicus, and their associated ectoparasites with three weather factors i.e., maximum biweekly mean temperature, minimum biweekly mean temperature as well as biweekly mean relative humidity as significant drivers of the rodent and their associated ectoparasites presence were recorded. Results showed that the biweekly fluctuations of weather factors seem to be mostly a reaction wards condition in altering the activity of both the rodents and their associated ectoparasites. Both species had three periods of activity in the two years of study and four and five periods of activity of the ectoparasites on R. rattus frugivorous and R. norvegicus. The highest biweekly variation in rodent's population was observed on the date 12 March and 10th September for the two species respectively.  Also, a significant positive and negative correlation between the climatic conditions and the population activity of the two rodents and their ectoparasites is dependent on the periods of the activity. The combined effect of the three weather factors on the fluctuation of population activity of the two species of rodents was ranged from 78.9 to 98.03% and from 55.31 to 99.11% for R. rattus frugivorous and R. norvegicus during the three periods of activity through the two years of study.  The simultaneous effect of the three tested weather factors on the fluctuation of population activity of rodents and their ectoparasites were varied through periods of activity. The temperature and relative humidity were two key factors that influenced the seasonal fluctuation of rodents and ectoparasites.