Certain biological aspects of the Egyptian praying mantis Miomantis paykullii (Stal, 1871) were studied in the laboratory. Results indicated that ootheca contained an average of 52.4 nymphs, with a mean length of 15.0 mm. The total duration period of nymphal stage required 64.1±10.54 and 54.8±6.54 days for female and male respectively. The generation period was 99 days at daily mean of temperature 25.9Cº and relative humidity percentage 45.0%. Six nymphal instars were recorded for male whereas, seven instars were found for female. The fecundity of M. paykullii through the oviposition period was 336.2±56.78 nymph per female.