This paper presents the results of a field experiment, whose aim was to investigate the potential of dissolved cow dung to cause anopheles larval population reduction in Yala swamp, western Kenya. Field experiments were conducted in two fish ponds located within the drained part of a wetland, and two swamp pools in undisturbed parts of the wetland. The experimental pond was treated with decomposed cow dung, while control pond and swamp pools were not treated. Data collection involved regular larvae sampling and water quality measurements in order to compare mosquito larval densities among the habitats based on variations in physic-chemical parameters. The species of anopheles mosquitoes identified were Anopheles gambiae complex and Anopheles funestus. The distribution and abundance of mosquito larvae was significantly associated with water quality parameters such as pH (r = -0. 48; P < 0.01), DO (P < 0.01), Conductivity (r = -0.11; P < 0.01) and Turbidity (r = -0.57; P < 0.01). The results show that cow-dung treatment significantly reduced Anopheles species population in the experimental pond without diminishing the dissolve oxygen concentration levels required for diverse biota. Thus, cow-dung has potential to control aquatic stage of malaria vectors, and further experiments could help to refine its use as a tool for larval source reduction in rural settings. This can facilitate community-based vectors control in rural areas where numerous transient mosquito breeding habitats occur.