Context National vaccine recommendations in the United States target an increasing number of vaccine-preventable diseases for reduction, elimination, or eradication. Objective To compare morbidity and mortality before and after widespread implementation of national vaccine recommendations for 13 vaccine-preventable diseases for which recommendations were in place prior to 2005. Design, Setting, and Participants For the United States, prevaccine baselines were assessed based on representative historical data from primary sources and were compared to the most recent morbidity (2006) and mortality (2004) data for diphtheria, pertussis, tetanus, poliomyelitis, measles, mumps, rubella (including congenital rubella syndrome), invasive Haemophilus influenzae type b (Hib), acute hepatitis B, hepatitis A, varicella, Streptococcus pneumoniae, and smallpox. Main Outcome Measures Number of cases, deaths, and hospitalizations for 13 vaccine-preventable diseases. Estimates of the percent reductions from baseline to recent were made without adjustment for factors that could affect vaccine-preventable disease morbidity, mortality, or reporting. Results A greater than 92% decline in cases and a 99% or greater decline in deaths due to diseases prevented by vaccines recommended before 1980 were shown for diphtheria, mumps, pertussis, and tetanus. Endemic transmission of poliovirus and measles and rubella viruses has been eliminated in the United States; smallpox has been eradicated worldwide. Declines were 80% or greater for cases and deaths of most vaccine-preventable diseases targeted since 1980 including hepatitis A, acute hepatitis B, Hib, and varicella. Declines in cases and deaths of invasive S pneumoniae were 34% and 25%, respectively. Conclusions The number of cases of most vaccine-preventable diseases is at an alltime low; hospitalizations and deaths have also shown striking decreases.