Abstract: Method and device for determining the formation factor of underground zones from drill cuttings. The device comprises a cell (1) associated with a device for measuring the electrical conductivity of the cell with the content thereof. The cell containing the drill cuttings is filled with a first electrolyte solution (A) of known conductivity (?A). After saturation of the drill cuttings by first solution (A), the global electrical conductivity (?*A) of the cell with the content thereof is determined. After discharging first solution (A), the cell containing the drill cuttings is filled with a second electrolyte solution (B) of known conductivity (?B), and the global electrical conductivity (?*B) of the cell containing the second solution and the cuttings saturated with the first solution is determined. The cuttings formation factor (FF) is deduced therefrom by combination of the measurements.