Aquatic pollution resulting from extensive usage of organotin compounds has been of great concern due to their deleterious effects in organisms. However, organotin contamination in deep-sea ecosystems has not yet been studied. The present study was attempted to determine butyltin compounds (BTs), including mono- (MBT), di- (DBT), and tributyltin (TBT) in deep-sea organisms collected from Suruga Bay, Japan, in order to elucidate the contamination status and accumulation characteristics. The organisms were collected between 135 and 980 m in the aphotic bathyal zone and compared with those collected from shallow waters. Total butyltin (Sigma BT: MBT + DBT + TBT) concentrations in the tissues of deep-sea fish, crustaceans, cephalopods, echinoderms, and gastropods were up to 980, 460, 460, 130, and 21 ng/g wet wt, respectively. These levels were lower than those in shallow-water organisms from the same bay but comparable to those reported in industrialized areas like Tokyo Bay, suggesting the expansion of BT pollution in deep-sea ecosystems. Deep-sea organisms from Suruga Bay contained much higher levels of BTs than previously reported organochlorine concentrations. BT accumulation appeared to be less lipid dependent. Among BTs, TBT was the predominant compound except in cephalopods, suggesting a fresh input of TBT into the deep-sea environment. To our knowledge, this is the first report on the detection of organotin residues in deep-sea organisms.