Purpose: To determine the effects of expiratory muscle strength training (EMST) frequency on maximum expiratory pressure (MEP). Method: We assigned 12 healthy participants to 2 groups of training frequency (3 days per week and 5 days per week). They completed a 4-week training program on an EMST trainer (Aspire Products, LLC). MEP was the primary outcome measure used to determine the effect of training frequency. Results: Participants who trained 3 days per week produced equivalent amounts of improvement in MEP compared with participants who trained 5 days per week. An overall improvement in MEP over the 4-week training period indicated a 33% increase when the data was collapsed across the 2 training groups. Conclusion: The effects occurring with respiratory muscle strength training in healthy young adults are likely to be different from those occurring in patient populations. Therefore, the results of the present study suggest exploring the variable of training frequency in patient populations. Such knowledge will be informative for designing clinical protocols that are effective and may result in improved treatment compliance for those suffering from expiratory muscle weakness. (Contains 2 tables and 1 figure.)