In November 2000 in the Netherlands, an outbreak of Salmonella enterica serotype Enteritidis phage type 4b was investigated. Eating bean sprouts was the only exposure associated with S. Enteritidis pt 4b infection (matched odds ratio 13.0, 95% confidence interval 2.0-552.5). Contaminated seeds were the most likely cause of contamination of the sprouts. The sprout grower applied a concentration of hypochlorite solution that was too low for seed disinfection.