Objectives: The present prospective study aimed at objectively evaluating the relevance of a single horizontal Y-V vermilion plasty including orbicularis oris muscle repair for secondary correction of whistling deformities in unilateral as well as bilateral cleft lip cases. Study Design: Ten patients were included in the study (mean age 20.2±6.2 years). The size of the whistling defects was determined on photographs before and 12 months after surgery. Additional surgical procedures like columella lengthening and rhinoplasty were documented. Results: Seven minor and 3 moderate whistling defects were corrected. In 7 patients additional procedures were carried out. The data of the 12 months follow-up showed that the whistling defect was significantly reduced in size (p<0005). In 7 out of 10 patients the result of surgery was rated "good" and in 3 patients "moderate". Conclusions: The present prospective study is the first one to show on an objective basis that the presented technique allows reducing whistling deformities significantly with good overall results in the majority of the cases. Moreover, the technique can be combined with other corrective procedures like columella lengthening without problems. As a consequence, it is a relevant and universal surgical technique for the correction of whistling defects.