The purpose of this paper was to evaluate the incidence of complications after BCG vaccination in children from urban area of Lódź in 1994-1995 and to give their pathological and prognostic interpretation on the basis of immunological and Groër allergometric examinations. The obtained data demonstrate that postvaccinal complications occurred in 46 children, that is 0.7/1000 of vaccinated population. They were observed mainly in newborns (45.7%), whereas they were particularly rare in revaccinated six-year-old children (13%) and schoolchildren (8.7%). In half of the cases there was an evidence of ulceration and suppuration in the site of vaccination, in another half--suppuration of local lymph nodes with or without fistula. Immunological and allergometric examinations were carried out in 21 children with post-vaccinal complications and 21 children with normal post-vaccinal period. In both groups the following were the subjects of evaluation: values of B and T lymphocytes and their CD4 and CD8 subpopulations, lymphocytes proliferative response to mitogenic PHA doses and tuberculin, as well as IgG, IgA and IgM levels. Immunological and allergometric examinations indicated that immunosuppression was neither the cause nor the effect of BCG complications.