The whoop is heard in the land ever less frequently with the passing decades since pertussis immunization has become widespread. Pediatricians sequestered in suburbia may have relegated it to the status of a medical curiosity; but, pertussis remains an important cause of infant morbidity. In 1967, there were 9,718 cases reported to health officials; this is an impressive reduction from the 32,148 cases reported 10 years earlier, but it still represents more than four times the number of meningococcal infections recorded in 1967. Pertusis persists endemically in the disadvantaged segment of the population not reached effectively by preventive medicine, and there is occasional spillover to the rest of the population.