Nitride semiconductors are well known as important materials due to their unique electronic and optical properties. If it is possible to incorporate magnetic species (i.e. Mn or Fe) into nitrides, these may also be used as magnetic semiconductors for spintronics. Scandium nitride, shown to be a semiconductor, has been studied lately for its potential electronic applications.@footnote 1@ Since both MnN and ScN are known to exist with octohedral bonding,@footnote 2@ it seems likely that Mn may be soluble in ScN. Thus, we have undertaken a study of the growth of MnScN by molecular beam epitaxy. Mn@sub x@Sc@sub 1-x@N growth is initiated on a buffer of ScN grown on MgO(001). Growth has been performed for samples at substrate temperature between 350°C and 650°C with Mn/Sc intended flux ratios of 10 and 20%. For all samples, XRD reveals a clear alloy peak which is distinguishable from the ScN and MgO peaks. From the comparison of the alloy peak position with that of ScN and the expected peak position of MnN (based on separate studies of this binary compound@footnote 3@), the values of x are estimated and found to be in good agreement with the Mn/Sc flux ratios. RHEED patterns shows smooth growth on the ScN buffer at the initial stage. The evolution of the RHEED pattern depends on the substrate temperature and the Mn flux. For Mn/Sc ratio of 10%, the RHEED pattern show only a single phase with smooth growth; but for Mn/Sc ratio of 20%, some weak ring structures are observed after extended growth time, indicating a possible limit to the solubility of Mn in ScN. Studies of the magnetic properties of the MnScN alloy are underway. Work is supported by NSF. @FootnoteText@ @footnote 1@ H. A. Al-Brithen and A. R. Smith, Appl. Phys. Lett., 77, 2485 (2000); A.R. Smith et al., to be published. @footnote 2@ Suzuki et al., J. Alloys and Compounds 306, 66 (2000) @footnote 3@ H. Yang et al., Appl. Phys. Lett. 78, 3860 (2001).