Spacers are used in the treatment of children with asthma. It is advised to clean the spacers regularly. However, cleaning can influence drug delivery. One obvious reason to clean a spacer is prevention of bacterial contamination. Whether spacers are contaminated or not is unknown. We cultured spacers, brought in by children with asthma or recurrent wheeze who visited our outpatient clinic during a 4-month period. The spacers of 64 children were studied, and 24 (38%) were contaminated; most often (13 cases), Bacillus species were found. Only one spacer grew a potential pathogenic bacterium (Pseudomonas aeruginosa). No correlation with type of inhaler, duration of usage, drug, or visual aspect was found. Spacers, cleaned according to national guidelines, were not less contaminated. Bacterial contamination of spacers is frequent, but the bacteria cultured are not pathogenic. Intensive cleaning of spacers does not influence the level of contamination with environmental bacteria.