Abstract: A warm-up garment for maintaining warmth in a single arm and shoulder area of a wearer, comprising a single sleeve having an upper end with an opening for receiving the wearer's hand and arm therethrough, and a lower end having a lower opening for receiving the wearer's hand therethrough. A body portion is attached to the sleeve adjacent the upper end opening and includes front and back panels joined across a top and a side edge adjacent the sleeve and extending diagonally across the torso of the wearer from the upper end of the sleeve to an area under the wearer's arm opposite the sleeve. The warm-up garment also includes an attachment panel having a first end attached to the back panel and a second end adapted for being extended from the back panel around the area under the wearer's arm opposite the sleeve to the front panel and for releasably securing the front and back panels around the body of the wearer without encircling the neck of the wearer.