SrRuO3 is an itinerant ferromagnet with TC=165 K and CaRuO3 is a metallic paramagnet down to at least 30 mK. These materials are known to be narrow d-band metals, the physical properties of which are highly sensitive to small perturbations such as chemical doping. In this article, we report results of resistivity, specific heat, and magnetic susceptibility measurements on Na doped SrRuO3 and CaRuO3. Resistivity measurements show a change from metallic to nonmetallic behavior for Na concentration of 12% with the ferromagnetic ordering temperature depressed in Sr1-xNaxRuO3. The nonmetallic behavior in the x=0.12 sample is supported by specific heat measurements which are suggestive of a partial opening of an energy gap and brings into question the role of itineracy in the magnetic ground state. Ca1-xNaxRuO3, with x=0.00, 0.05, and 0.09, remains metallic and shows no evidence of long range magnetic order for all x. © 1999 American Institute of Physics.