AbstractThe Casiguran Agta constitute a Negrito hunter‐gatherer society in northeastern Luzon. The hypothesis presented is that this population has suffered serious decline over the last half ‐century. Demographic data collected over a 24‐year period are used to substantiate this hypothesis. Agta figures on crude death rate, rate of natural decrease, infant mortality, life expectancy at birth, and homicide are among the most extreme known for any human population. Reasons for this decline are described, with emphasis on the factor of hom