Resistivity () and thermopower ͑S͒ of spinel-type compounds CuIr 2 S 4 and CuIr 2 Se 4 have been measured at temperatures from 2 to 900 K under magnetic field from 0 to 15 T. The thermopower is positive in the metallic phase of both compounds at high temperatures, as well as in the low-temperature insulating state of CuIr 2 S 4 . The positive thermopower of the insulating phase implies p-type charge carriers, in agreement with the recent photoemission results. The low-temperature resistivity of CuIr 2 S 4 is in good agreement with the Efros-Shklovskii variable-range hopping conductivity mechanism: ϭ 0 exp͓(T*/T) 1/2 ͔. The most striking result is that the resistivity of the metallic phases is well described by an exponential-type temperature dependence in a wide temperature range from 2 K to at least 900 K. This unusual result for metals type of the resistivity temperature dependence, as well as other features in the transport properties, imply a nonconventional conductivity mechanism. The magnetoresistivity ⌬ is positive and proportional to H 2 , while magnetothermopower ⌬SϭS(H,T)ϪS(0,T) is very small for both compounds at all temperatures.