Quantitative T2 mapping has potential for prostate cancer discrimination. However, current methods are typically 2D, require long scan times and may lead to inaccuracies if using an oversimpliﬁed exponential model. We propose rapid 3D T2 mapping based on accelerated 3D multi shot T2-prepared bSSFP acquisition combined with dictionary-based matching. The dictionary of signals was generated using a simulation framework taking into account the specifics of the acquisition, and was then matched to the acquired images to retrieve T2 values. The proposed approach was tested in healthy subjects enabling the acquisition of 3D T2 mapping of the whole prostate in 4min.