The objective of this study was to determine whether there were increases in respiratory and cardiovascular hospital admissions among residents of lower Manhattan after the destruction of the World Trade Center. The authors used hospital admission records from 1991 to 2001 with a diagnosis of respiratory, cardiovascular, or cerebrovascular illness and a residential address in lower Manhattan or Queens. The authors assessed the change in admissions by comparing lower Manhattan to Queens (the control area) and before and after 9/11 admissions in lower Manhattan. They found the following significant increases in hospital admissions: for respiratory illnesses during the weeks of 9/11/01 and 10/16/01; asthma during the week of 9/11/01; cardiovascular during the weeks of 9/18/01 and 10/9/01; cerebrovascular during the weeks of 9/11/01, 9/18/01, 10/2/01, and 10/9/01. There was an immediate increase in respiratory admissions after the disaster and a delayed increase in cardiovascular and cerebrovascular admissions.