Background: Pools with lifeguards are often perceived to represent a safe environment for swimming. Objectives: To examine how often fatalities occurred in pools with lifeguards and what factors were common in these incidents. Design: Case series. Setting: USA. Subjects: A case was defined as a death in a swimming pool with at least one lifeguard that occurred in the USA from 2000 to 2008. Potential cases were identified from media accounts using Lexis-Nexis and ProQuest databases. Supplemental information was obtained through internet based searches and review of death certificates. Results: A total of 140 deaths from 37 states were identified. Of decedents, 109 (78%) were children and 93 (66%) were males. African Americans accounted for 44% of deaths among those of known race. 104 (74%) fatalities occurred during May through August; 85 (61%) deaths occurred in outdoor pools. Sites for fatal incidents included 53 (38%) municipal pools, 21 (15%) community organisations, and 20 (14%) schools. The median swimmer to lifeguard ratio was 13:1. Decedents were initially identified in the pool twice as often by non-lifeguards (eg, other swimmers or bystanders) as by lifeguards. Conclusions: Deaths in pools with lifeguards are uncommon, but do occur. Groups most affected include children, males, and African Americans. While lifeguards provide an important layer of protection at swimming pools, they alone cannot prevent all drownings. Additional safety measures are needed.