I've been using something like this and it has always been correct: nSlices = reader.GetOutput().GetDimensions()[2] Eric -- View this message in context: http://vtk.1045678.n5.nabble.com/vtkDICOMImageReader-Get-number-of-files-tp5725897p5725898.html Sent from the VTK - Users mailing list archive at Nabble.com.