Decreasing of number of cases as well as incidence rate of hepatitis type B and type A, and increasing of pertussis, leptospirosis, encephalitis and some other diseases was noted in Poland in 1997. The biggest percentage of deaths was caused by tuberculosis--43.1%, sepsis--over 21.9% and hepatitis--10.6%. Introduction of ICD-10 as well as strikes of health workers in Poland in 1997 caused undernotification especially of deaths.