For microscopical and statistical evaluation of different laboratory methods and stains for detecting circulating microfilariae of Dirofilaria immitis in ten naturally infected local stray dog's positive to canine heartworm Ag ELISA kit. All blood samples were examined by three methods modified Knott's technique, serum concentration test, and Türk's solution concentration test and three laboratory stains methylene blue, giemsa, and acridine orange stains were used to dye the precipitate of the modified Knott's technique. Results showed that the slides prepared from the serum were easy to examine (there are no erythrocytes) compared with the slides prepared from the precipitate of the modified Knott's technique. The slides prepared using the Türk's solution were more transparent and freer of cell debris. The length and width of the microfilariae detected by the three methods did not change significantly. Our conclusion from this study is that Türk's solution concentration test and the serum concentration test can be used in place of the modified Knott's technique to detect microfilaremic dogs. Acridine orange staining can also substitute for methylene blue and giemsa stains for faster results.