The need to fill a blank range with zeros often occurs when dealing with data that is downloaded from a mainframe. Recently I've seen several examples that utilize a loop structure to fill a blank range with zeros. Rather than using loops, below is an example that utilizes the SpecialCells method to fill a range.

Sub FillBlanksWithZeros()
    Dim Rng As Range
    On Error GoTo ErrHandler
    Set Rng = Range("A1:B10")
    Rng.SpecialCells(xlCellTypeBlanks) = 0
    Exit Sub

ErrHandler:
    MsgBox "Error # " & Err.Number & " - " & Err.Description
End Sub

The SpecialCells method is much faster than using a loop structure.