We conducted a prospective study to examine the influence of discontinuing peak flow monitoring (PFM) in stable asthmatics who had already been properly educated and were monitoring their own peak expiratory flows (PEF). All subjects had been performing PFM for at least 3 months prior to their entry into the study, and PFM was then stopped for a period of 3 months. Comparisons of endpoints were made between a period of 3 months prior to, and after discontinuing PFM. Forty patients with a mean age of 52 were studied. Only one patient experienced a single emergency room visit either before or after discontinuing PFM. Short courses of oral steroids were administered in 6 patients (15%), both before and after discontinuing PFM. There was no significant change in pulmonary function, beta 2-agonist use and asthma symptoms during a 3-month period before and after discontinuing PFM. These results suggest that simply continuing PFM in stable, educated asthmatics may have little impact on asthma control, although its long term influence should be carefully examined.