Abstract We have calculated electron collisional excitation strengths for transitions among the 18 LS states 2 s 2 2 p 3 4 S o , 2 D o , 2 P o ; 2 s 2 2 p 2 ( 3 P )3 s 4 P , 2 P ; 2 s 2 p 4 4 P ; 2 s 2 2 p 2 ( 3 P )3 p 2 S o , 4 D o , 4 P o , 4 S o , 2 D o , 2 P o ; 2 s 2 2 p 2 ( 1 D )3 s 2 D ; 2 s 2 2 p 2 ( 3 P )4 s 4 P , 2 P ; and 2 s 2 2 p 2 ( 3 P )3 d 2 P , 4 P , 2 D of N I using the R -matrix method. These states are represented by fairly extensive configuration-interaction wave functions. The 18 LS states give rise to 40 fine-structure levels. The calculated excitation energies agree well with the measured values. The collision strengths for fine-structure transitions are obtained using an algebraic transformation to intermediate coupling. The collision strengths are integrated over a Maxwellian distribution of electron energies to obtain effective collision strengths over a wide temperature range from 1000 to 600,000 K. The effective collision strengths obtained are tabulated for transitions among the lowest 12 LS states.