Stuttering and autism can co-occur and when they do it presents a significant communication challenge. This study examined the effectiveness of a modified version of the fluency rules program (FRP; Runyan and Runyan, Stuttering and related disorders of fluency, in 2007) to reduce stuttering frequency in a man with autism spectrum disorder (ASD). The participant’s percentage of stuttered words (%SW) was calculated during conversational interactions with multiple conversation partners both within and outside of the clinic treatment sessions. Visual inspection methods revealed a reduction in %SW from an average of 14.5 %SW during baseline to 2.07 %SW during the withdrawal phase. The mean baseline reduction in %SW from baseline to the second treatment phase was 91.8 %. The FRP holds promise for reducing %SW in persons with ASD who stutter.