An apparatus for determining the conditions of a pipeline comprising: a central body having a substantially cylindrical form; a first crown of petals connected to the central body, wherein each petal extends from the central body until it touches the internal wall of the pipeline and wherein each petal comprises at least one deformation sensor and at least one roughness sensor; a sliding device integrally connected to the central body (101) in a more advanced position with respect to the first crown of petals (102), wherein said sliding device can be a second crown of petals (103) identical to the first crown of petals or a foam pig (104) suitably perforated. Said apparatus can also comprise salinity sensors (110) and pH measurement sensors (111) for measuring some of the chemical properties of the fluid contained in the pipeline. A further object of the invention relates to a method for determining the conditions of a pipeline which uses an apparatus according to the present invention.