Purpose: Misarticulation of /r/ is among the most challenging developmental speech errors to remediate. Case studies suggest that visual biofeedback treatment can establish perceptually accurate /r/ in clients who have not responded to traditional treatments. This investigation studied the response of children with persistent /r/ misarticulation to a course of traditional treatment and a course of biofeedback treatment. Method: Eleven children with /r/ misarticulation completed 10 weeks of individual treatment consisting of 4-6 weeks of traditional treatment followed by 4-6 weeks of biofeedback treatment. Progress was measured by tracking correct /r/ productions within treatment and probing /r/ in words at 3 time points. Results: At the group level, there was no difference in independent judges' ratings of /r/ sounds produced by the children before and after traditional treatment. However, /r/ sounds produced after biofeedback treatment were significantly more likely to be rated by the judges as perceptually correct. Eight of the 11 children made measurable gains in the accuracy of isolated /r/ produced within treatment, with 4 showing significant generalization to untreated /r/ in words. Conclusion: This descriptive study shows that treatment incorporating spectral biofeedback can facilitate accurate /r/ production in children with treatment-resistant errors. A follow-up period using traditional intervention methods may be necessary to encourage generalization.