Abstract: Abu Za`baal Lakes are three newly formed lakes lying in North of El-Qalubiya Governorate. Water samples were collected seasonally from surface and near-bottom waters of these lakes. Physico-chemical and bacteriological analysis of the studied lakes were investigated. The results revealed that the recorded pH values of the studied lakes` waters were on alkaline side. High total bacterial counts (saprophytic and parasitic) and high bacterial indicators of sewage pollution (total and faecal coliforms as well as faecal streptococci) were recorded in Summer. The total counts of gram-negative bacteria were also recorded, where E. coli, Klebsiella pneumonia, Salmonella choleraesuis, Enterobacter aerogenes, Yersinia pseudotuberculosis and Citrobacter freundii were found to be dominant organisms. As indication of trophic status of the studied lakes, seasonal and regional variations of bacterial reproduction rate (generation time), bacterioplankton biomass, daily production of bacterial biomass and hydrolytic bacterial activity were determined. Generally, first lake maintained the highest values of bacterial reproduction rate, bacterial biomass, daily production of bacterial biomass and hydrolytic bacterial activity compared with the other two lakes. Also, the near-bottom water recorded the highest bacteriological parameters compared with those in surface water layers of the investigated lakes. Seasonally, these parameters recorded the highest levels during Summer.