Requirements and effects of strip injection of C(4+) at 6 MeV/u into carbon ion synchrotrons are studied. The setup is composed of three chicane dipoles, one Lambertson septum, and one carbon stripping foil at a thickness of 60 microg/cm(2). The required length of the injection section is about 4.1 m. The emittance growth due to multiple Coulomb scatterings is studied.