A recently proposed method for obtaining the oxide thickness based in current-voltage pairs in the Fowler-Nordheim regime is analysed in the CrSiO2Si(p) structures with oxide thickness in the range 50-60 Å. After measuring the capacitance-voltage, and current-voltage characteristics, the Fowler-Nordheim plot is obtained, yielding the CrSiO2 barrier height. Then, applying an iterative technique the oxide thickness is obtained for each I-V pair. The results show that in spite of the oscillatory structure exhibited in the Fowler-Nordheim regime the accuracy in the oxide thickness obtained in this way is much greater than in other electrical methods. © 1987.