A shelving system (10) with height adjustable shelves is described, with reference to a portable trolley with shelves for holding medical equipment, although it is also applicable to portable and stationary shelving systems for many uses. The shelving system (10) comprises at least one shelf (18), at least one support (14) and at least one locating bracket (36) for locating the shelf (18) on the support (14). The locating bracket (36) includes at least two engagement members (38) engageable with the support (14), and locking means (40) to lock the locating bracket (36) and the shelf (18) to the support (14).