The study aimed to assess the mosquito larval abundance in seasonal man-made larval habitats associated with rainfall in Kassala town, eastern Sudan during the short rainy season 2016, evaluate the physicochemical characteristics, and determine the relationships between such characteristics and immatures abundance. Immature stages were collected monthly in the selected larval habitats, identified into genera by morphological criteria and counted. Physical characteristics were estimated by visual inspection. Water sample was collected from each larval habitat and analyzed for chemical characteristics. A total of 5020 mosquito larvae and pupae were collected and identified into two genera, Anopheles and Culex. All the investigated larval habitats were found exposed to direct sunlight with still water. The monthly mean values of measured chemical characteristics did not vary significantly except for the following parameters: pH, calcium and magnesium. Occurrence of Anopheline immatures was only associated, positively, with nitrates (r = 0.53; p < 0.05) while the presence of Culex immatures was associated, negatively with pH value (r = -0.56; p < 0.05) and positively, with sulphate (r = 0.56; p < 0.05). Correlations found between certain chemical parameters and larval abundance, perhaps, confirms the influence of these parameters on the abundance of two mosquito genera in their breeding habitats.