Iinfluenza and ARI intensity in Bulgaria was slowly increased during week No 42 (14.10.2013 - 20.10.2013) and the total incidence per 10,000 population was 63.63 (during week No 41 the incidence was 62.64). From a total of 381 562 persons under surveillance, belonging to all age groups, a total of 2 428 ARI cases have been reported (during week No 41 the cases were 2 390). The incidence was highest in the age group 0-4 yrs (261.21 per 10,000 population), followed by age group of 5-14 yrs (173.62 per 10,000).