The aim of conformal radiation therapy is to deliver the dose as high and as uniform as possible to diseased tissue sparing all the other parts, without causing unwanted and unnecessary side effects for the patient. Difficulties to achieve this goal start with the determination of the threedimensional volumes of interest and end up in realizing a three-dimensional uniform and maximal as possible, the dose distribution. The technique of intensity-modulated radiotherapy (IMRT) as form of conformation in radiation therapy is a real revolution. One of the newest attempts in this field, which reaches to have a great success, is the use of multi-leaf collimators (MLC). It is not the unique new technique. In fact the use of therapeutic ions, especially carbon ions and protons is the technology of the actual future which is really the challenge in conformation of dose to targets, thanks to energy deposition characteristics of hadronic beams. An appropriate treatment planning system is strictly necessary to take full advantage of the novel technique. We have developed, for this purpose, an analytical code in C++ language, running on Unix platform. The package presented, is a special code system dedicated to the planning of radiotherapy with energetic ions. ANCOD is an analytical code using the voxel-scan technique as an active method for irradiating the patients. It is based on an iterative algorithm to determine the best fluencies to realize the optimal dose distribution, delivering a maximum of dose on the target volume and a minimum of dose distribution all around, especially on organs at risk. As input, the code use experimental data of linear energy-loss of a particular set of initial kinetic energies, and as a clinical data a complete set of CT images with contours of volumes of interest. Inverse planning techniques are implemented in order to obtain the initial energies needed for each beam to have a uniform target dose distribution. The package can determine the fluencies and energies of several thousand of pencil beams in few minutes. The performances of the program are tested with a full simulation. ♣ Partially supported by ICSC-World Laboratory, Lausanne, Switzerland. ! Partially supported by IBA, Ion Beam Application, Louvain-La-Neuve, Belgium.