This report provides estimates of the lifetime and annual incidence of certain infectious diseases of children in various demographic groups. Data on the social and health care impact of the diseases in terms of limited activity, days spent in bed, school days lost, contacts with physicians, hospitalizations, surgery, and use of medication are presented. The data are taken from the 1988 National Health Interview Survey on Child Health. The nine diseases for which statistics are reported are: ear infection, tonsillitis, pneumonia, diarrhea, urinary tract infection, mononucleosis, hepatitis, meningitis, and rheumatic fever. Results indicated that: (1) a total of 38 percent of children had at least one of the diseases; (2) ear illness was the most common illness, affecting 25 percent of children; (3) among infants, 10 percent had ear infection, 3 percent had diarrhea, and 3 percent had pneumonia; (4) tonsillitis was the most common disease among teenagers; (5) most diseases were reported more frequently among White children than among Black or Hispanic children; and (6) girls were 5 times as likely as boys to have urinary tract infections. A reference list of 16 items is provided. Appendixes include a description of the data collection and statistical methods used in the study and definitions of terms used in the report. (BC)