Phase relationships of the HDDR (hydrogenation, disproportionation, desorption and recombination)-treated Sm₃(Fe,M)₂₉-type alloy with chemical composition of Sm₉Fe₆₅Co₂₀V₆ were studied by X-ray diffraction (XRD) and by thermomagnetic analysis (TMA). The alloy was disproportionated into a mixture of SmH_x and α-Fe at high temperature under hydrogen gas. The disproportionated material was recombined into a mixture of Sm-(Fe,M) (M = Co and/or V) and α-Fe phases. The structure of the Sm-(Fe,M) phase was dependent upon the recombination conditions, and a detailed phase diagram showing the phase relationships in the HDDR-treated alloy has been established. The Sm-(Fe,M) phase in material recombined above 900℃ had the Sm₂Fe₁₇-type structure, and it exhibited the SmFe₇-type structure when recombined at temperatures ranging from 700℃ to 850℃. Recombination below 650℃ led to the SmFe₃-type structure of the Sm-(Fe,M) phase. Curie temperatures of the Sm-(Fe,M) phases in the recombined material were significantly higher than those of the corresponding stoichiometric phases. It was suggested that the chemical composition of the Sm-(Fe,M) phases may be significantly different from that of the corresponding stoichiometric phases. All the HDDR-treated Sm₉Fe₆₅Co₂₀V₆ materials showed the soft magnetic features regardless of the phase constitution.