Electronic absorption and magnetic circular dichroism spectra are reported for the A (2)Delta, B (2)Sigma(-), and C (2)E(+)<- X(2)Pi transitions of methylidyne radicals isolated in a Kr matrix at cryogenic: temperatures. The results are interpreted in the framework of a model in which the X(2)Pi term is split by combination of spin orbit and crystal-field interactions with the atoms of the host matrix. Analysis of the zeroth moments of the spectra yields an empirical spin-orbit coupling constant A(Pi) = 11 +/- 2 cm(-1) and orbital reduction factor kappa = 0.26 +/- 0.05, corresponding to a crystal-field splitting of V(Pi) = 43 +/- 10 cm(-1) for the X(2)Pi term. For the A 2 Delta excited-state term, analysis of the first MCD moments gives a spin orbit coupling constant of A(Delta) = 4.4 +/- 0.9 cm(-1).