A novel garden bean cultivar, designated HMX4127 is disclosed. The invention relates to the seeds of garden bean cultivar HMX4127, to the plants of garden bean line HMX4127 and to methods for producing a bean plant by crossing the cultivar HMX4127 with itself or another bean line. The invention further relates to methods for producing a bean plant containing in its genetic material one or more transgenic and to the transgenic plants produced by that method and to methods for producing other garden bean line derived from the cultivar HMX4127.