Dhaka city (23°42′N latitude 90°22′E longitudes), on the eastern banks of the Buriganga River. The city lies on the lower reaches of the Ganges Delta and covers a total area of 300 square kilometers (120 sq mi). Dhaka city is a hot, wet, humid and has a distinct monsoon season, with an annual average temperature of 26 °C and monthly means varying between 19 °C in January and 29 °C in the month of May. Approximately 87% of the annual average rainfall of 2,123 millimeters (83.6 inches) occurs between May and October. The present study was conducted from November, 2014 to February, 2016. During study period, 49 places from 10 different parts of Dhaka city, Bangladesh were selected for the watwr sampling. The selected locations were Sadarghat, Bangshal, Wari, Jatrabari, Tejgaon, Shahbagh, Badda, Khilgaon, Rampura and Mailbagh of Dhaka City corporation area. The samples were collected within July, 2015 from different location in the Dhaka city. Further experiments i.e., identification, counting and preserving the mosquitoes, culturing and isolation of preserved water sample was carried in the Entomology laboratory, Department of Zoology and fungal flora has been identified in the Plant Pathology laboratory, Department of Botany, Jagannath University, Dhaka, Bangladesh from August, 2015 to February, 2016. Sample collection Water samples were collected from stagnant drains of Dhaka. Water samples were collected by using dipper and transparent plastic jars of specific volume (150 ml). For further analysis, the sampling jars were carried to the Entomology laboratory. Identifying larvae and pupa Firstly, 100 ml volume of larvae-containing water was measured by measuring cylinder (100 ml). Then the water was placed on the Petri dish and the numbers of larvae and pupae of mosquitoes were counted carefully. Larvae and pupae of Aedes and Culex were identified according to the method of the fauna of British-India, including Ceylon and Burma. Isolation of fungi from water sample After counting larva and pupa of mosquito, water samples were preserved in refrigerator at 40C for further analysis. Isolation of required fungi from water samples were done following Serial Dilution Technique. At first, 1 ml of water sample was added into the test tube containing 9 ml of sterile distilled water and shaken well. This suspension was marked as stock suspension. Then 1 ml of stock suspension were transferred by sterile pipette into another test tube containing 9 ml of sterile distilled water for tenfold (1:10) dilution and then further diluted up to 105 and 106 dilutions and plating in triplicate plates were made from 10-5 and 10-6 diluted samples. Potato Dextose Agar (PDA) medium fortified with Streptomycin Sulphate (0.1 mg/ml) was poured into petri plates, each containing 15 ml of PDA medium. Then, 1 ml of each of the diluted water samples were transferred into a sterilized PDA petri plate by using sterilized pipettes, and were incubated at room temperature for 3 days. At the end of the incubation period, the developing fungi colonies were counted, identified and calculated for each sample. Identification of fungi The fungal colonies appearing on petri plates were su-bcultured into separate petri plates containing PDA medium for identification. Macroscopic characteristics such as size, color and nature of colonies, margin of colonies, presence and absence of concentric ring, sclerotia, colony diameter, exudates, pigmentation on front and back of the culture etc. were observed. Microscopic characteristics including structure and color of mycelia, shape, color and size of spores or conidia and conidiophores, vesicle, metulae, phialides, etc. were studied by mounting small portion of culture on a glass slide with lactophenol-cotton blue and lactophenol separately. The adhesive side of the tape was touched onto the surface of the colony at point intermediate between the center and periphery. Then adhesive side of the tape was adhered over an area on a glass slide with a drop of lactophenol or lactophenol-cotton blue separately. The slides were then examined microscopically for size and shape of vehicle, arrangement of sterigmata and spores, color of spores etc. under 10X, 40X and 100X objective lenses of compound microscope (Novel XSZ-107T). A small portion of the colony was taken into lactophenol-cotton blue solution on a glass slide and spread firmly with the help of sterilized needles. It was covered with a cover glass then examined microscopically. Photograph of the fungal colonies were taken with a digital camera (Nikon COOLPIX-S3500 7X wide) and photomicrographs of the microscopic structures of fungi were taken with the aid of Euromex CMEX-10 digital USB camera, Holland. Measurements of the microscopic character were recorded with the help of Image Focus 4 (version 2.4) software. For proper recording of collected samples, the raw data was recorded in a table which was categorized according to mosquito (larvae and pupae) and fungal flora. The identified fungal isolates were also recorded in a spreadsheet using Microsoft Office Excel.