Unconfined Compressive Strength (UCS) is a parameter of interest in geomechanics problems analysis: Wellbore Stability, quantitative constrains stresses in situ magnitudes, assessment sanding potential and selection of bit drilling. It is intuitive that the drilling would have to reflect the strength rock properties under the real conditions in the bottomhole. However rate of penetration (ROP) is dependent of a number of other parameters. ROP models have been proposed for the different types of drilling bits and evaluated and verified in wells in North Sea and Canada. These models when used in an inverse methodology they allow estimate the drilling strength, S. This work was addressed to correlate drilling strength (S) and UCS. When this objective was reached the UCS can only be calculated of drilling parameters (WOB, RPM, ROP). Two correlations for shale and sandstone lithologics are proposal by the study field in Campos basin. Satisfactory results were obtain when these correlations were evaluated and compared with estimated UCS profiles from geophysical well logs. Space UCS/S vs. WOB/RPM used to correlate the strengths seems very promissory for other applications such as: planning/optimization of a new well (selecting the best combination of WOB and RPM), diagnostic and evaluation of the drilling in Real Time TR.