The purpose of writing this review on micro balloons is to accumulate the recent literature with a special focus on the novel technological advancements in floating drug delivery system to achieve gastric retention. Micro balloons (Hollow microsphere) promises to be a potential approach for gastric retention. Micro balloons drug-delivery systems are based on non-effervescent system containing empty particles of spherical shape without core ideally having a size less than 200 micrometer. Micro balloons drug delivery systems have shown to be of better significance in controlling release rate for drugs having site specific absorption. They are gastro retentive drug-delivery systems, which provide controlled release properties. The advantages, limitation, methods of preparation of hollow microsphere, applications, polymers used in hollow microspheres, characterizations of micro balloons and formulation aspects with various evaluation techniques and marketed products are covered in detail.