Nineteen strains of Sicilian-type and two strains of Naples-type phlebotomus fever virus were recovered from wild-caught Phlebotomus papatasi collected in Cairo. Egypt. Maximum virus transmission appears to occur in August and September, with some activity extending to November. In a comparison of source materials for virus isolation, nonengorged specimens were superior to those containing blood. Suckling mice were a suitable host for primary isolation of both virus types; blind passages and lengthy courses of adaptation to this host were not required. The recovery of Sicilian-type virus from male sandflies was interpreted as evidence for transovarial passage of the virus.