A national survey of the attitudes of physicians toward the selection of human growth hormone products and factors affecting physicians' prescribing decisions was conducted. A survey was mailed to 800 pediatric endocrinologists. Recipients were asked to rank eight qualities of human growth hormone therapy from a patient's perspective, to rate the importance of each of 15 factors to the prescribing of human growth hormone products, and to respond to a hypothetical clinical situation set up to assess opinions on the interchangeability of human growth hormone products. The physicians were also asked whether they thought all human growth hormone products were clinically equivalent and, if so, whether a formulary should be limited to one brand of product for all indications. The net response rate was 29%. Physicians ranked insurance coverage and out-of-pocket expenses as the most important factors from the patient's perspective and reported efficacy, patient comfort or compliance, insurance coverage, and drug cost as the most important factors to consider when selecting a human growth hormone product; patient preference was reported to be the least important. A total of 209 physicians (92%) considered all human growth hormone products to be clinically equivalent; not quite half of these favored limiting a formulary to one brand of product. Concerning the hypothetical situation, 210 of 226 (93%) respondents indicated that they would not switch all patients receiving one product (product A) to another product (product B) and 192 of 223 (86%) that they would not switch all patients receiving product B to product A. A national sample of pediatric endocrinologists agreed on the clinical equivalence of most human growth hormone products but not on limiting a formulary to one brand of product.