Despite the substantial increase in research activity in machine learning for MR image reconstruction, no large scale raw k-space data set is publicly available. This makes it challenging to reproduce and validate comparisons of different approaches, and it restricts access to work on this problem to researchers associated with large academic medical centers. This abstract introduces the first large-scale database of MRI data for reconstruction. The database currently includes about 7500 raw MRI k-space data sets from a range of MRI systems and clinical patient populations, with corresponding images derived from the rawdata using reference image reconstruction algorithms. Approximately 30000 additional clinical image datasets not directly associated with the rawdata are also included, and we plan to add to the database over time.