The isoscalar spin strength in C12 has been studied in the inelastic scattering of polarized 400 MeV deuterons. The measurements were carried out over an angular range from 3° to 7° and an excitation energy range from 11 to 58 MeV (momentum transfer range from 0.34 to 0.92 fm−1). Previously unknown spin excitations were found in the 20-MeV region and over a broad range in the continuum with a cluster of strength around 30 MeV. The results are compared with spin-flip probability measurements in proton scattering. Below 35 MeV of excitation energy, the isoscalar relative spin response is strongly enhanced above the noninteracting Fermi gas value of 0.5. Above 35 MeV of excitation the spin response drops below 0.5.