Sub LookUp3()
Dim lastrow As Long, i As Long
Dim lookuprange As Range
lastrow = Sheet1.Range("A" & Rows.Count).End(xlUp).Row
Set lookuprange = Sheet1.Range("A1:B" & lastrow)
With Sheet2
For i = 2 To lastrow
.Cells(i, 2) = Application.VLookup(Sheet1.Cells(i, 1), lookuprange, 2, False)
Next i
End With
End Sub