Six months after the delivery, the women in observed cohort were sent further questionnaire of ELSPAC set, PN-6/2 („My child“): the questions explored the nutrition, health status and behaviour of the child in the time after the delivery. Smoking habits of mothers were investigated in questionnaire PN-6/1, sent out in the same term. The differences between the sets of children born to smoking and non-smoking mothers were statistically assessed with use of SPSS and EPI INFO programmes. 4,581 women answered the questions within investigation half a year after the delivery. 76.2% of them did not smoke at all, 16.8% smoked less than 10 cigarettes a day and 7.0% smoked more than 10 cigarettes a day. At least 7% of children born to non-smoking mothers, 14% of children born to weak smokers and 45% of children born to middle and strong smokers stayed certain time a day in a smoky spaces. In six months, 30% of non-smoking and 2.6% of smoking women breast fed their children. Mothers who were smoking in the time of six months after delivery gave more often that their children were suffering from more severe health problems, respectively that they were sick nearly all the time. The children of smokers showed significantly increased frequency of all observed signs of respiratory system damages including the complications (middle ear inflammations). In the first half a year of life, almost twice as much of children of strong smokers were admitted to hospital when compared to children of non-smoking mothers (17.7% vs. 9.6%). Only two (!) mothers from all set admitted, that respiratory problems of the child could be related to its stay in smoky space. This alarming absence of knowledges about riskiness of passive smoking has to be solved as a priority by widely concieved health education.

        Key words: passive smoking, infants morbidity