OBJECTIVES/HYPOTHESIS: Determine if increasing annual temperature is associated with an increase in the prevalence of otolaryngologic respiratory diseases. STUDY DESIGN: Cross-sectional study. METHODS: Patients and disease variables were extracted from the National Health Interview Survey for the calendar years 1998 to 2006 adult sample. Corresponding average annual temperature statistics were obtained from the National Climatic Data Center. The disease prevalences of hay fever, sinusitis, chronic bronchitis, and jaw/face pain (control group) were determined and tabulated according to mean annual temperature and compared graphically. Regression analysis for disease prevalence according to mean annual temperature was conducted. RESULTS: A total of 851,584 adults were sampled with a mean age of 35.7 years and a male:female ratio of 0.93:1. The overall disease prevalences for the disease conditions across all years of the study were (+/-95% confidence interval): hay fever (9.2% +/- 0.1%), sinusitis (15.0% +/- 0.2%), chronic bronchitis (4.5% +/- 0.1%) and pain in jaw/front of ear (4.5% +/- 0.1%). Regression analysis did not find a significant relationship between average annual temperature and the prevalence of disease for hay fever, jaw pain, or chronic bronchitis. A statistically significant but small regression coefficient (0.004) was noted for an increasing prevalence of sinusitis with increasing annual temperature (P Euro Surveillance (Bulletin Europeen Sur Les Maladies Transmissibles; European Communicable Disease Bulletin) .031). CONCLUSIONS: Changes in mean annual temperature did not influence the prevalence of hay fever but did influence the prevalence of sinusitis over a 9-year period. Given the strong prevalence of hay fever and sinusitis, the effect of global warming on the otolaryngologic disease deserves continued epidemiologic surveillance.