BACKGROUND AND METHODS Achromobacter species leads to chronic infection in an increasing number of CF patients. We report 2 cases of Achromobacter ruhlandii cross-infection between patients after well-described indirect contact. RESULTS Both cases were young, stable, CF patients without chronic infections and with normal FEV1, but experienced clinical deterioration after visits to the home of a CF patient with A. ruhlandii infection and after sharing facilities with an A. ruhlandii infected CF patient on a skiing vacation, respectively. Both cases became positive for A. ruhlandii in airway secretions and were colonized with A. ruhlandii in their sinuses. Aggressive, long-term antibiotic treatment led to clinical stability. One of the cases developed chronic A. ruhlandii infection. CONCLUSION A. species can cause cross-infection even after a short period of indirect contact between infected and non-infected CF patients. Patients should be followed closely for several months before the possibility of cross-infection is ruled out.