Exposing crystalline CuAsF6 to < 1 atm CO produces the homoleptic copper carbonyl cations [Cu(CO)](+), [Cu(CO)(2)](+), and [Cu(CO)(3)](+). These complexes were characterized by IR and Raman spectroscopy and by tensimetric titrations. The IR and Raman data are consistent with a two-coordinate, linear structure for the [Cu(CO)(2)](+) cation and with a three-coordinate, trigonal-planar structure for the [Cu(CO)(3)](+) ion. The compounds [Cu(CO)(2)][AsF6] and [Cu(CO)(3)][AsF6] represent the first examples of isolable polycarbonyls of Cu(I).