Binary phase diagrams of the systems: n-docosane: n-tricosane (C22H46: C23H48), n-tricosane: n-tetracosane (C22H46: C24H50) and n-docosane: n-tetracosane (C22H46: C24H50) have been established by means of structural and differential scanning calorimetry analyses. On the basis of these results and of X-ray examination of forty one ternary mixtures, it is proposed the ternary phase diagram (C22H46: C23H48: C24H50) at room temperature. This work has indicated the existence of limited terminal solid solutions near the three pure n-alkanes and three domains of orthorhombic intermediate phases (noted beta(1)＇, beta(1) ", beta(2)＇) identical to those observed in the binary systems. X-ray experiments have showed that the phases beta(1)＇, beta(2) ", situated on the both sides of the middle intermediate phase beta(1)＇, are isostructural as in the binary systems.