Experimenters are inextricable aspects of pain research. State-of-the-art clinical trials in the field of pain employ “double blind” methodology to minimize the influence of experimental demand characteristics and placebo effects on outcome. At an even more basic level, effects of the “mere presence” of an experimenter have been shown to impact subject reports pain research (e.g., Craig et al., 1974). Human research articles in Volume 99 of the International Association for the Study of Pain's journal “Pain” were reviewed. Brief notes, reviews, commentaries, editorials, responses and studies in which participants had no contact with experimenters (e.g., Internet-based experiments) were excluded. The primary investigator and one trained investigator manually reviewed articles and electronically searched using key words (e.g., experimenter, investigator, researcher, assistant, technician, interviewer). Information was recorded about the number of experimenters and their role in the social context of experiment (e.g., verbally administered pain measures versus provision of paper and pencil measures to participants). While 100% of studies reported participant characteristics (e.g., gender, ethnicity) and sample size, only 52% alluded to or indicated anything about the persons who collected data. Four studies out of twenty-three (17%) reported the number of experimenters utilized, and only one study (4%) described any experimenter characteristics (e.g., number of years experience) other than occupation (e.g., nurse). Seven (30%) of the studies reported information related to the experimenter's role in the social context in which pain measures were obtained. Given research evidence that experimenter factors can impact ratings provided by subjects in pain research, those variables should be routinely listed in published reports of pain research that uses human subjects. However, this review indicates that experimenter variables are rarely described. More emphasis needs to be directed towards consideration of the interpersonal and sociocontextual variables that might be operating in human pain research.