A semiconductor device includes a substrate having first and second regions, first fin groups spaced along a first direction on the first region, each of the first fin groups including adjacent first and second fins having longitudinal directions in a second direction intersecting the first direction, and third to fifth fins spaced along a third direction on the second region, the third to fifth fins having longitudinal directions in a fourth direction intersecting the third direction. The third through fifth fins are at a first pitch, the first and second fins are at a second pitch equal to or smaller than the first pitch, each of the first fin groups is at a first group pitch greater than three times the first pitch and smaller than four times the first pitch, and a width of the first and second fins is same as width of the third fin.