Background Preauricular sinuses are congenital abnormalities caused by a failure of fusion of the primitive tubercles from which the pinna is formed. When persistent or recurring inflammation occurs, surgical excision of the infected tissue should be considered. Preauricular defects inevitably occur as a result of excisions and are often difficult to resolve with a simple suture; a more effective reconstruction technique is required for treating these defects. Methods After total excision of a preauricular sinus, the defect was closed by a plastic surgeon. Based on the depth of the defect and the degree of tension when apposing the wound margins, the surgeon determined whether to use primary closure or a posterior auricular flap. Results A total of 28 cases were examined. In 5 cases, including 2 reoperations for dehiscence after primary repair, reconstruction was performed using posterior auricular transposition flaps. In 16 cases of primary closure, the defects were closed using simple sutures, and in 7 cases, closure was performed after wide undermining. Conclusions If a preauricular defect is limited to the subcutaneous layer and the margins can be easily approximated, primary closure by only simple suturing may be used to perform the repair. If the defect is deep enough to expose the perichondrium or if there is tension when apposing the wound margins, wide undermining should be performed before primary closure. If the extent of the excision exposes cartilage, the procedure follows dehiscence of the primary repair, or the tissue is not sufficiently healthy, the surgeon should use a posterior auricular flap.