Sandfly fever virus (SFV), which is classified in Phlebovirus genus, Bunyaviridae family, is widely seen in the Middle East and Mediterranean basin. SFV has four serotypes known as Sicilian (SFSV), Cyprus (SFCV), Naples (SFNV) and Toscana virus (TOSV). Sandfly fever, which is transmitted to human by different species of sandflies, especially Phlebotomus spp., starts with acute onset of high fever and lasts for three days. Headache, anorexia and myalgia are the most common symptoms. The aim of this study was to present the clinical and laboratory findings of the patients who were diagnosed during sandfly fever outbreak in Kirikkale province (located in central Anatolia in Turkey) during July 2009. A total of 20 patients from different districts of Kirikkale province with the history of fly bite and with the clinical findings of fever, myalgia-arthralgia, headache, conjunctival hyperemia and gastrointestinal symptoms such as diarrhea and nausea-vomiting were admitted to the Infectious Disease Unit of State Hospital. All the patients were followed up after hospitalization. A sandfly fever outbreak has been considered in the area since the cases shared a common history of insect bite, similar clinical and laboratory features in a particular time interval. The first patients from each different districts were accepted as the "index case" and 11 patients' serum samples have been sent to Refik Saydam National Public Health Agency, Virology Reference and Research Laboratory, Ankara. Serum samples were analyzed by using a commercial mosaic immunofluorescence test (IFT) (Euroimmun, Germany) to detect IgM and IgG antibodies against SFSV, SFCV, SFNV and TOSV. SFV-IgM positivity was demonstrated in 8 out of 11 patients (Naples virus in 5, Sicilian virus in 3 cases), while all of the cases were IgG negative. Of seropositive patients, two were female and six were male with a mean age of 30.7 (age range: 16-53) years. Sandfly fever was diagnosed in five cases by the positive IgM results and in three cases by the detection of IgM seroconversion in the second samples collected 6 days later. Clinically, fever and myalgia-arthralgia were detected in all of the cases, diarrhea and nausea-vomiting in 7, headache in 5 and conjunctival hyperemia in 1 of 8 seropositive patients. The evaluation of laboratory findings revealed leukopenia (1800-3800 cell/mu l) in all cases, thrombocytopenia (69000-140.000 cell/mu l) in 7, elevated AST (42-271 IU/L) in 7, elevated ALT (46-173 IU/L) in 5, elevated CK (185-1560 U/L) in 6 and elevated CRP (5.18-83.6 mg/L in 5 of 8 patients. All the patients were treated symptomatically without any sequella and discharged with complete cure. Turkey is a country in the Mediterranean basin and it is known that there is a favorable sandfly fauna in Anatolia. Therefore sandfly fever should be considered in patients presenting with fever and arthralgia-myalgia and with a history of insect bite especially during summer months.