A method for determining the distance of an aircraft from an offset runway during a landing by offset approach, the offset runway being situated at a distance D from a main runway equipped with at least one elevation beacon, comprises at least the following steps: determining the height h at which the aircraft is situated, height determined with respect to a point T1 of the offset runway, height measured by a radioaltimeter with which the aircraft is equipped, determining the angle of elevation φ of the MLS mode by using the information of the elevation beacon provided by an elevation beacon with which said main runway is equipped, determining the value of the distance ρ of the aircraft from the azimuth beacon (10) by using the following formula ρ = ( h Tan ⁡ ( φ ) - D ⁢ ⁢ 2 Cos ⁡ ( θ ) ) 2 + h 2 , and, using said distance ρ to obtain a point of location of the aircraft in an offset runway reference frame.