Iinfluenza and ARI intensity in Bulgaria was slowly increased during week No 41 (07.10.2013 - 13.10.2013) and the total incidence per 10,000 population was 62.64 (during week No 40 the incidence was 52.94). From a total of 381 562 persons under surveillance, belonging to all age groups, a total of 2 390 ARI cases have been reported (during week No 40 the cases were 2 020). The incidence was highest in the age group 0-4 yrs (275.24 per 10,000 population), followed by age group of 5-14 yrs (175.20 per 10,000).