The Federal Government is currently planning a large, prospective birth cohort study known as the National Children's Study that will potentially involve 100,000 children and their families. The observation period will start as close to conception as possible and will continue for 20 years after birth. Given the magnitude and expense of such a large study, sample collection methods that are amenable to acquisition of samples exclusively by the participants themselves followed by direct shipment to the analysis laboratory present a cost-effective alternative to technician-based sampling procedures. In this pilot study, the ability of participants in three age cohorts to collect environmental and biological samples according to prescribed protocols was evaluated. The cohorts consisted of parents and their children in the ages of 0-1 year, 3-5 years, and 6-8 years old. Biological and environmental samples collected during the study included urine, hair, saliva, breast milk, duplicate diet, tap water, vacuum cleaner dust, floor surface dust wipes, air samples, cotton sock dosimeters, and humidity/temperature measurements. Sample collection instructions and materials were prepared, subjected to evaluation and modification using a test population, and shipped to participants over a 12-month period. Participants were requested to collect the samples, complete questionnaires, and return the samples to the laboratory within defined time periods. Upon receipt at the laboratory, the condition of the samples was assessed by visual inspection and the details of the receipt and evaluation were logged into a computer database; queries were subsequently used to assess compliance. In some cases, chemical analysis was used to further evaluate sample integrity.