UNLABELLED: The purpose of mastectomy for the female-to-male transgender patient is to produce a masculine appearance of the chest. A number of algorithms have been proposed for selecting the surgical technique; these have generally been based on the degree of breast ptosis and the quality and elasticity of the skin. We present a series of subcutaneous mastectomies operated on by 1 surgeon during the last 2 decades. Based on our experience, we suggest a classification system for selecting surgical technique. METHODS: Data were collected from the files of female-to-male transgender persons who underwent surgery during 2003-2019. The data included background and surgery information. Pictures from the clinic's archive of the patients before, during, and after surgery were collected and analyzed. RESULTS: In total, 220 mastectomies were performed on 110 patients aged 13.5-50 years (mean 22.5 ±6.1). The excision averaged 443 g per breast (range: 85-2550). A periareolar approach was performed in 14 (12.7%), omega-shaped resection (nipple-areola complex on scar) in 2 (1.8%), spindle-shaped mastectomy with a dermal nipple-areola complex flap approach in 38 (34.5%), and a complete mastectomy with a free nipple-areola complex graft in 56 (50.9%). Complications included 2 hypertrophic scars, 6 hematomas requiring revision surgery, 3 wound dehiscences, and 3 cases of partial nipple necrosis. CONCLUSIONS: Analysis of the data led to a proposed classification for female-to-male transgender mastectomy (Wolf's classification), based on skin excess and the distance between the original and the planned position of the nipple-areola complex.