High-cycle fatigue properties at 4 K, 77 K and 293 K were investigated in forged-Inconel 718 nickel-based superalloy with a mean gamma (γ) grain size of 25 μm. In the present material, platelike delta phases precipitated at γ grain boundaries and niobium enriched-MC type carbides precipitated coarsely. The 0.2% proof stress and the ultimate tensile strength of this alloy increased with decreasing temperature, without decreasing elongation or reduction of area. Fatigue strength in longer-life region did not increase in response to increments in tensile strength, since fatigue cracks initiated internally irrespective of the test temperatures. Fatigue cracks formed crack initiation sites consisting of facet-like structures. These facet-like structures mainly corresponded to coarse carbides at higher stress amplitude and crystallographic facets formed through transgranular initiation and growth of micro cracks at lower stress amplitude.