The change in effective stress condition resulting from sampling of saturated clays is examined. A link, in terms of Hvorslev strength parameters, ce and ∖a/e, is established between the perfectly undisturbed sample strength and the in-situ strength. The theoretical analysis and the supporting experimental data indicate that for normally consolidated saturated sensitive clays, the in-situ strength and pore-pressure coefficient, Af, are significantly different from those measured on even perfectly undisturbed samples in unconsolidated-undrained triaxial compression tests. An expression is proposed for the evaluation of the in-situ strength of normally consolidated saturated clays in terms of the soil strength parameters, ce and ∖a/e, and the pore-water pressure coefficient, Af, in-situ.