An outbreak of folliculitis caused by Pseudomonas aeruginosa serotype O:7 occurred among the guests of a hotel in St. John's, Newfoundland, Canada, and the source of the infection was traced to the hotel whirlpool. Of 36 persons who used the whirlpool, 26 (72%) developed folliculitis within 1 to 5 days after exposure; the attack rate was significantly higher for children (90%) than for adults (50%). The rash characteristics were consistent with those of Pseudomonas folliculitis previously described (T. L. Gustafson, J. D. Band, R. H. Hutcheson, Jr., and W. Schaffner, Rev. Infect. Dis. 5:1-8, 1983). This is considered to be the first outbreak in which P. aeruginosa serotype O:7 has been incriminated. Published reports to date of outbreaks of Pseudomonas folliculitis associated with the use of whirlpools, hot tubs, swimming pools, etc., were reviewed.