We evaluated what proportion of families have a consumer-grade pulse oximeter, why they bought one, and how they choose to use it. We hypothesized that children followed in cardiorespiratory clinics would be more likely to have an oximeter than children attending a more general clinic. We carried out a cross-sectional study using a convenience sample of children attending a respirology, cardiology, or gastroenterology clinic at a children's hospital. Consenting guardians completed a survey. Two-hundred families completed the survey. Fifty-three (26.5%; 53/200) had an oximeter at home. The proportion of children attending a cardiorespiratory clinic who had an oximeter was higher than another clinic (p = 0.08), but 15.5% of children attending the latter also had access to one. Of devices not funded by government insurance, over 80% of devices were "fingertip" clamp-style oximeters, and 50% were purchased online. Most devices were used only when the child was ill (83.7%; 36/43). Only about 1/3 of families had received education about using an oximeter, and a similar proportion had compared their oximeter to a medical-grade device. Only 2.4% (1/42) respondents did not feel that their device was "somewhat" or "very" accurate. The oxygen saturation that would prompt seeking emergency care was similar to most pediatric acute care guidelines. Many children, particularly those with cardiorespiratory conditions, have access to consumer-grade pulse oximeters. Asking about the presence of an oximeter should be part of the pediatric history, and families responding affirmatively should be offered education.