With the aim of studying the stability range of the Zr₂Fe intermetallic when adding Nb, the range of existence of the cubic ternary phase (λ₁) and the corresponding two-phase field between them, four samples were analyzed, each one containing 35 at.% Fe and different at.% Nb: 0.5, 4, 10 and 15. Optical and scanning electron metallographies, X-ray diffraction, microprobe analysis and Mössbauer Spectroscopy were performed to determine and characterize the phases present in the samples. Results show that the Zr₂Fe compound accepts up to nearly 0.5 at.% Nb in solution, since the Zr₂Fe+λ₁ region is stable in the (0.5-3.5) at.% Nb range. To summarize these results an 800°C section of the ternary Zr-Nb-Fe diagram, in the studied zone, was proposed.