This study is an effort to establish the contribution that pneumonia made to the causes of death in antiquity in the Andean coastal región of northern Chile. In addition, results were compared with modern populations from the 1920s, before effective therapy was widely available for this disease. A group of 197 spontaneously ("naturally") desiccated, mummified human remains from South America's western coast between about 19 to 21 degrees South Latitude (South Central Andes) was examined. The status of pathological, desiccated lungs was classified into the categories of normal and acute pneumonia on the basis of gross examination. The percentage of deaths (all ages) due to pneumonia in these mummies was 22.3% compared to the 10.1% (p = <0.01) for all ages for deaths in the United States in the 1920s during the preantibiotic era. However, infants (0-2 years) were especially vulnerable (45.9% in antiquity, 13.7% in 1921).While the age-related pattern between the two populations was similar, results indicated that the percent of pneumonia deaths were substantially higher in antiquity than for the 1920s period, and that they were highest for infants less than 2 years of age, possibly due to immunological factors and environmental conditions.