Fatigue cracks are among the most commonly occurring anomalies in metallic structures. Detection and characterization of cracks is of utmost significance to prevent complete failure of structures. The detection of a fatigue crack using microwave nondestructive testing methods is complicated by the fact that the indication of such a crack is very small compared to the environmental disturbances (e.g., surface irregularities, variations in the lift-off, etc.). Furthermore, orientation/location of the crack is typically unknown a priori. In this paper, an enhanced microwave resonator probe is introduced for the detection of fatigue cracks in metals. The performance of the probe which operates at 800 MHz is demonstrated on a real fatigue crack with width measured to be less than 3 μm near its tip at a lift-off of 1mm, The performance is also compared to a conventional Ka-band rectangular aperture probe, which was unable to detect the crack.