Sulbutiamine (isobutyryl thiamine disulfide) is a lipophilic derivative of thiamine used for the treatment of asthenia and other related pathological conditions. It is available over-the-counter in several countries either as a component of nutritional supplements or as a pharmaceutical preparation. The presence of sulbutiamine in urinary doping control samples was monitored to evaluate the relevance of its use in sports. As one of the sulbutiamine metabolites has very close retention time and the same characteristic ion (m/z 194) as the main boldenone metabolite, the raw data files generated from the screening for anabolic steroids were automatically reprocessed to identify the samples containing sulbutiamine. It was found that of ca. 16 000 samples analyzed in the Russian laboratory during 2009, about 100 samples contained sulbutiamine. It is important to note that most of these samples were collected in-competition, and sulbutiamine concentration was estimated to be greater than 500 ng/ml. This may indicate that sulbutiamine was intentionally administered for its ergogenic and mild stimulating properties.