Introduction: The cutaneous leishmaniasis has been regularly spread in Iran. Jask County, which has been located in the eastern part of Hormozgan province, had the most cases of patients. The present study aimed to investigate on the fauna and biology of sand flies. Methods: In this descriptive, cross sectional study, during 2007-2008, sand flies were captured using sticky papers and CDC miniature light traps. Flies species were identified using microscopic method. Parity rate was examined by dissection to cheqeur accessory glands for pigments. The ELISA method was used for detection of anthropophagic index. Results: A total of 8123 sand flies were caught, so as 57.52% were male and 42.49% female (39.07% and 60.93% were caught indoor and outdoor, respectively). The fauna was identified 8 species (2 Phlebotomus and 6 Sergentomyia). Phlebotomus major was reported for the first time in Hormozgan province. P. papatasi and P. salehi were the dominant species. Monthly activity of sand flies begins at the end of Esfand, lasting to mid Azar with two peaks, the first in Ordibehesht – Khordad and the second one in Mehr-Aban. The parous rate was high (³70%) at the second peak. The dominant species showed high anthropophagic index (29.6% and 18%, respectively).Conclusion: Although the sand flies fauna is poor in Jask County but they are highly diverse. P. papatasi and P. salehi transmit the Leishmania parasite from reservoir rodents to human. According to the endophility, residual spraying twice a year (Esfand and Shahrivar) could be effective in hyperendemic villages.