1. Interference is due to superposition of two distinct waves coming from two coherent sources. Diffraction is a result of superposition of the secondary wavelets coming from different parts of the same wavefront.
2. In interference, all bright bands are of same intensity; while in diffraction pattern, all bright bands are not of same intensity.
3. In interference pattern, intensity of minima is generally zero or very small and there is a good contrast between bright and dark fringes. In diffraction pattern, intensity at minima is never zero and there is a poor contrast between bright and dark bands.
4. The width of interference fringes may or may not be equal; but the width of diffraction bands is always unequal.