BACKGROUND Asthma care plans typically include complicated written instructions. Customized, audio-recorded instructions may bridge health literacy gaps and improve treatment plan understanding. OBJECTIVE To measure the effects of a recordable greeting card-style tool (Talking Card) on asthma control and parental care of children with asthma. METHODS Multisite randomized trial in two primary care clinics, including children 4-11 years old with uncontrolled asthma and their parents. Parent-child dyads were randomized to usual care of asthma or usual care plus the Talking Card. Dyads completed three asthma-focused visits over 3 months. At the visit, card recipients received customized instructions recorded by the pediatrician onto an audio chip in the card. Asthma control was measured by using the Childhood Asthma Control Test. Card use and parental satisfaction were measured by parental survey (card arm only). Outcomes were analyzed by using generalized estimating equations and frequency distributions. RESULTS Sixty-four dyads participated and attended 166 clinic visits. Card use was associated with a 1.6-point increase in Childhood Asthma Control Test score (p = 0.02) and a clinic visit regardless of card use with a three-point increase (p < 0.001). Satisfaction and self-efficacy were high among the card users. The mean satisfaction score was 8.9 of 10, with 96% agreeing or strongly agreeing that the card helped them take better care of asthma. CONCLUSIONS The Talking Card, a novel audio communication tool, was associated with improved asthma control and deemed highly desirable by parents and children struggling to control asthma. This inexpensive portable tool may be useful in other chronic disorders and in locales with low literacy and poor access to digital technology.