The attack rate for pneumonia increases with increasing age and with residence in a nursing home. The rate of hospitalization of Halifax County, Nova Scotia, Canada, residents with pneumonia was 1 in 1,000, while for nursing home residents it was 33 in 1,000. The overall mortality rate for community-acquired pneumonia requiring hospitalization was 21.9%. Mortality was age-related: Seven percent of those 30 years of age or younger died, while 38% of those in the 81 to 90 year age group died. Comorbidities increased with increasing age from 0.73 +/- 0.81 for those 30 years old or younger to 2.75 +/- 1.47 for those 71 to 80 years of age. The most common comorbidities were chronic obstructive pulmonary disease, ischemic heart disease, hypertension, diabetes mellitus, malignancy, alcoholism, and neurological disease. The acquired immunodeficiency syndrome was a significant comorbidity among those 50 years of age or younger. Age-dependent trends were observed in the use of antimicrobial therapy: Cefamandole and aminoglycosides were prescribed more frequently with increasing age, whereas after the age of 61 years, the use of erythromycin declined. Penicillin usage was not age-dependent. Resource (hemograms, chest radiographs, blood chemistry, blood gases, and sputum culture) use peaked at the 50 to 60 year age group.