Exhibit 12.1

KLA-Tencor Corporation

Computation of Ratio of Earnings to Fixed Charges

 

     Year ended June 30,    Nine months ended
March 31,
     2007    2006    2005    2004    2003    2008    2007
     (in thousands, except ratios)

Earnings:

                     

Income before income taxes and minority interest

    $ 677,235    $ 377,858    $ 583,076    $ 270,388    $ 114,986    $ 462,717    $ 480,935

Add back fixed charges:

                     

Interest expense

      2,781      2,175      1,750      519      386      1,466      2,095

Charge for unamortized bond issuance costs

      0      0      0      0      0      0      0

Interest portion of rental expense

      3,243      2,788      3,891      4,141      5,394      3,118      2,331
                                                

Total adjusted earnings

      683,259      382,821      588,717      275,048      120,766      467,301      485,361

Fixed charges:

                     

Interest expense

      2,781      2,175      1,750      519      386      1,466      2,095

Charge for unamortized bond issuance costs

      —        —        —        —        —        —        —  

Interest portion of rent expense

      3,243      2,788      3,891      4,141      5,394      3,118      2,331
                                                

Total fixed charges

      6,024      4,963      5,641      4,660      5,780      4,584      4,426

Ratio of earnings to fixed charges

      113.4      77.1      104.4      59.0      20.9      101.9      109.7

For purposes of calculating the ratio of earnings to fixed charges, earnings is the amount resulting from adding (a) the earnings from continuing operations before income taxes and minority interest, and (b) fixed charges. Fixed charges for these purposes include (a) interest expense, (b) amortization of bond issuance costs, and (c) one-third of rental expense, which KLA-Tencor considers to be a reasonable approximation of the interest factor included in rental expense.