The thermal conductivity&lgr;(x=0,0.15,0.3,0.6;T=2–200 K) and electrical resistivity&rgr;(0⩽x⩽0.5;T=6–300 K) of layered crystalsNb1−xSnxSe2are measured in theabplane. The metal– semiconductor transition is observed atx≈0.5. The magnitude of the resistivity anomaly observed at 33 K and associated with a transition to the charge density wave phase increases with increasingxforx>0.15. The thermal conductivity of the metallic samples(x<0.5)increases with temperature atT>90K, which is in accord with the nonlinearity of the&rgr;(T)dependence. The absence of such an increase in&lgr;(T)for a semiconducting sample indicates that this singularity is connected with the electronic subsystem. The observed nonmonotonicity of the&rgr;(x)dependence may be associated with the existence of a sharp peak in the electron density of states near the Fermi level. Approximation of the&lgr;(T)dependence reveals the existence of a phonon scattering mechanism with a relaxation rate proportional to the square of the frequency. ©1998 American Institute of Physics.