Septic arthritis is a rapidly destructive form of joint disease. The most common causative agents in children are Staphylococcus aureus and Kingella kingae, followed by group A Streptococcus and Streptococcus pneumoniae, and in neonates, enterobacteracea and group B Streptococcus. In this paper, we describe a previously healthy toddler with septic arthritis of the shoulder joint caused by Brevundimonas vesicularis. Prompt treatment with cefuroxime resulted in a full recovery. This is the first report of septic arthritis in humans caused by this microorganism, and the first description of B. vesicularis infection in an immunocompetent child.