High influenza morbidity due to new antigenic strain AH1N1 was announced in Mexico in spring 2009. Influenza pandemic caused by the virus AH1N1/2009 spread around the world. Two pandemic waves were noted in most European countries: the first one was due to summer months migration, the second wave started in the beginning of common influenza season. We present features of both waves in children from the district of Lodz. We describe mild clinical course in 14 children who came from holiday in Spain with influenza and who were hospitalized and treated with osltamimivir due to unpredictable course of new influenza. We also present 22 influenza cases of the autumn pandemic wave, when children with severe complications of influenza and children from high risk groups were hospitalized and treated with antivirals. Experience that we have gained during 2009 influenza pandemic indicates that International Influenza Control System is very efficient, however more flexibility is required in application of treatment and prophylaxis procedures with new influenza strains. Applied methods of control should mostly depend on the virulence of pandemic strain.